Online Arbitrage UK: The Honest Guide for Amazon Sellers

Online arbitrage is simple to describe and harder to do well: you buy discounted products from UK retailer websites, send them to Amazon, and sell them for more than they cost you all-in. The gap between those two numbers — after Amazon’s fees, FBA fulfilment, prep and VAT — is your profit.

Most guides to online arbitrage in the UK stop at the description. They list thirty retailer names, tell you to “check Keepa”, and leave out the parts that decide whether you actually make money: what the fees really are, how VAT changes the maths depending on whether you’re registered, why most products you check will be unprofitable, and how a single wrong product match can wipe out a week of good buys. This guide covers all of it. I run a sourcing engine I built myself that reads more than 80 UK retailer sites around the clock, so where I make a claim about what sourcing actually looks like, it comes from my own logs rather than a hunch — and where I sell something, I’ll say so plainly.

What online arbitrage is (and how it differs from retail arbitrage)

Online arbitrage (OA) and retail arbitrage (RA) are the same business with a different sourcing surface. RA means walking physical shops and scanning shelves; OA means browsing retailer websites from a desk. The economics are identical — buy low at retail, sell at Amazon’s price, keep the difference after fees.

The practical differences matter, though:

• Reach. OA lets you source from hundreds of retailers in an evening, from anywhere. RA is limited to the shops you can drive to.
• Repeatability. An online deal can be checked, bought, and re-bought when it restocks. Software can watch it for you. In-store clearance is one-and-done.
• What you miss. Some of the deepest clearance in the UK only ever happens on physical shelves and never appears online. RA reaches stock OA can’t.
• Competition. An online deal is visible to every other OA seller in the country at the same moment. A clearance shelf in one branch is visible to whoever’s standing in front of it.

Most sellers who take this seriously end up doing both — that’s what I see across my membership. If you want the in-store side, I’ve written a separate guide to retail arbitrage in the UK covering sourcing, margins and starting capital for the physical version. And once either model is working, the natural scale-up path is wholesale — buying direct from distributors rather than retailers — but that’s a later problem.

Why online arbitrage suits UK sellers

Three things make the UK a genuinely good place to run this model:

• Retailer density. The UK has an unusually deep bench of national retailers with real online clearance activity — Argos, Boots, Superdrug, B&M, Smyths, The Works, Lookfantastic and dozens more — all shipping nationally, all repricing constantly.
• A predictable discount calendar. Black Friday and Cyber Monday in late November, Boxing Day and the January sales, end-of-season clearance around late June–July and again after Christmas, and Back to School through August–September. Retailers cut hard in these windows while Amazon prices lag behind — that lag is the whole edge.
• FBA does the operations. Fulfilment by Amazon handles storage, delivery and customer service, which is what makes this runnable part-time. Your job reduces to finding, checking and buying stock.

It’s also one of the cheapest legitimate ways into e-commerce. There’s no warehouse, no minimum order quantities, no wholesale accounts to open. But be honest with yourself about the starting pot: you need £500 minimum. Anyone telling you £200 is enough is setting you up to stall — you’ll have it all tied up in stock with nothing left to move with when the next deal appears. £1,000 is where it gets comfortable and sourcing stops feeling restrictive.

The workflow, step by step

Every profitable OA purchase goes through the same loop. Skipping a step is where money gets lost.

The economics that decide profit

Now we get onto the fees. Surprisingly, you don’t actually need to sit calculating any of this yourself — I use SellerAmp, which does it all for you: put in your cost price and sale price and it gives you your profit after every fee, right on the page you’re already looking at. Easy, simple — nobody wants to waste their evenings manually working out fulfilment bands. (Code AMAVIP gets you 50% off your first month if you fancy trying it.) That said, you should still understand what’s being taken and why, so here’s the full breakdown. (Or skip the reading and run your own numbers in my free profit calculator and FBA fee checker — same fee tables as below.)

This is where guides go vague and sellers go broke. The numbers below are current for 2026, taken straight from Amazon’s own UK pricing pages and its European FBA rate card effective 1 February 2026.

Amazon’s fees

Two 2026 changes worth knowing: Amazon cut fees by an average of £0.15 per unit across its European stores, with referral-fee reductions from December 2025 / January 2026 in low-price bands — for example, Clothing at £15 or under dropped from 8% to 5%, Home at £20 or under from 15% to 8%, and Grocery and vitamins at £10 or under from 8% to 5%. And the Low-Price FBA threshold widened to £20, worth roughly £0.40 per unit on newly eligible items. Cheap, fast-moving products got structurally more attractive this year.

VAT — the number that changes everything, twice

VAT is the most UK-specific part of the maths, and the reason a deal can be profitable for one seller and a loss for another on the same day at the same prices. There are two positions:

• Not VAT-registered. You don’t charge output VAT, so you keep the full sale price (minus fees). That’s an effective margin edge of around 17 percentage points on the sale side (one-sixth of the sale price) versus registered competitors. The downside: you can’t reclaim the VAT baked into your purchases — or your Amazon fees.
• VAT-registered. Roughly one-sixth of every sale price is output VAT owed to HMRC, which is a serious haircut. In exchange, you reclaim input VAT on stock, fees and prep. If you’re buying retail stock with VAT receipts, you’ll be on standard VAT accounting — that’s the route nearly everyone I work with takes.

You have to register once your taxable turnover passes £90,000 in any rolling 12 months — that’s the GOV.UK figure, in force since April 2024. Two traps inside it: it’s turnover, not profit, so an arbitrage business turning stock quickly hits it far sooner than the profit suggests; and HMRC counts every channel you sell on together — Amazon plus eBay plus anything else. You must apply within 30 days of the end of the month you crossed it.

One more fee-side wrinkle: since 1 August 2024, Amazon charges 20% UK VAT on its seller fees (referral, FBA, subscription). Registered sellers reclaim it; non-registered sellers simply pay 20% more in fees than the headline rates suggest. Any profit calculator that ignores this is flattering you.

Because the two positions produce genuinely different answers, every lead my engine publishes is priced under both VAT conventions before a member sees it. If you’re doing this by hand or spreadsheet, do the same — a deal that only works in one column is a decision, not a bargain.

Prep: home or centre

Every unit into FBA needs an FNSKU label and packaging to Amazon’s spec. Doing it at home is free — it just eats your evenings. UK prep centres in 2026 charge £0.35–£0.60 per unit for labelling, £0.20–£0.40 for polybagging, £2–£4 per outbound carton, and often a £20–£50 monthly membership (some charge none). The honest trade: prep fees buy back sourcing hours, and a prep centre gives you a business address so retailer parcels stop arriving at your front door. Put the per-unit figure in your deal maths either way.

Returns and the other quiet lines

I’ve yet to read another UK guide that models returns into ROI, and they’re real: a percentage of everything you sell comes back, some of it unsellable. I won’t give you a universal figure because there isn’t an honest one — it varies hugely by category — but a margin that only works at zero returns is not a margin. The same goes for storage fees on slow stock and the occasional retailer cancellation. Build slack into the buy decision rather than discovering it in the settlement report.

Where deals actually come from

First, the uncomfortable truth: most products aren’t deals

I can put a number on this from my own logs: my engine reads roughly 10,000 UK retailer pages a day, and around 7,000 of them die at “no discount at all” — full-price retail almost never beats Amazon after fees. The edge lives in clearance windows, voucher stacks and repricing lags, which is why finding them fast matters more than reading more pages.

Here’s what nobody selling you a retailer list mentions. My engine reads roughly 10,000 UK retailer pages a day, and its logs are unambiguous: the single biggest reason a page goes nowhere is no discount at all, and when a full-price catalogue product does get matched and priced against Amazon, the typical result is a loss once fees are counted. That’s not a broken tool — that’s what retail-versus-Amazon economics look like at full price. Margin lives in the exceptions: clearance, markdowns, vouchers, price glitches, and a handful of discount retailers whose everyday shelf price genuinely undercuts Amazon.

Which means the real question isn’t “which 100 websites should I check?” — it’s “how do I find the small fraction of pages that are actually mispriced today?” There are three ways.

Manual sourcing

Browsing retailer sale and clearance sections with an analysis extension open. Free, educational, and slow. Work the seasonal calendar above rather than browsing at random, and learn a few retailers deeply — their clearance behaviour, their cancellation habits with reseller-sized orders, their voucher patterns — rather than skimming fifty. A warning about the popular “top OA websites” listicles: several that rank well in Google still list Tesco Direct (closed in 2018), or describe Wilko as dead when the brand relaunched online under new ownership in late 2023 — stale in both directions. Stale lists are the norm in this niche.

Software scanning

Tools like Tactical Arbitrage ($59–$159/month depending on tier) crawl retail sites in bulk and match products to Amazon automatically. They genuinely widen your reach, with two caveats: most of the big-name scanners are built for the US market first — check the UK retailer list yourself before you hand over a card; and automated title-based matching is precisely where wrong-match errors breed — everything a scanner surfaces still needs the barcode-level verification from step 2.

Deal lists and leads services — including mine

Full transparency: I myself monitor 80+ retailer sites on autopilot for exactly these clearance windows — I built the engine that does it, and it’s what my members’ daily deal feed runs on. So yes, I have a horse in this race; judge the category on its logic, not my say-so.

Paid subscriptions where someone else does the finding and you do the buying. UK services range from roughly £30 to over £125/month depending on depth, list size and exclusivity — and yes, this is the category I operate in, so read this section knowing that.

The honest case against leads services, which I’d rather make myself than have you discover: a lead shared with hundreds of subscribers gets bought by hundreds of subscribers. Competition arrives on the listing within days, the price compresses, and the margin the deal sheet promised decays with every person acting on it. Any leads service that doesn’t acknowledge this is selling you the screenshot, not the outcome.

The honest case for them: finding deals is the single most time-expensive part of this business, and a good service compresses hours of scanning into minutes of decision-making — which is exactly what a part-time seller is short of. What separates services is verification depth and how the leads are found. Mine come from my own engine — the one reading more than 80 UK retailer sites continuously — which matches products by barcode wherever the retailer exposes one, applies strict title-identity checks where it doesn’t, and drops anything that fails verification before a member sees it, because a wrong match is worse than no match. You can see how the whole model fits together on my how it works page. Whether that’s worth £49.99/month for the Amazon FBA plan is your call to make with the numbers in front of you — the pricing page sets out exactly what’s included.

Cashback and vouchers: bonus margin, not core margin

TopCashback and Quidco pay 3–12% at major UK retailers when you buy through their tracked links, and on a borderline deal that’s the difference between profit and pass. The stacking order that works: retailer sale price, then a voucher code, then cashback on the net spend. The catch I’ve watched people learn the hard way: cashback claims frequently get declined when you use a voucher code the cashback site doesn’t itself list — so never buy a deal that needs the cashback to be profitable. Treat it as a bonus that usually arrives, not a line you rely on.

The tools worth having

The tool stack for OA is smaller than the listicles suggest. Three layers:

• Keepa (Premium around €29/month) for price and sales-rank history. Non-negotiable in my book — without history, every Amazon price is a rumour.
• SellerAmp SAS ($19.95–$49.95/month) for on-page analysis: it sits on the retail page and the Amazon listing and grades the deal — profit, ROI, eligibility, alerts for IP-risky brands — while you browse. It’s what I have my members run for checking deals, whatever the source of the deal is, and it’s the tool I’d pick for that job over anything else on the market. Full disclosure: SellerAmp is a commercial partner of mine and that’s my affiliate link — costs you nothing, and I’d recommend it regardless, but you should know that as you read this.
• A deal source — manual time, a scanner subscription, or a leads service, per the section above.

That’s genuinely it to start. Repricers, accounting tools and restock software all earn their place later, once there’s volume to manage.

Sign up through my link and these codes work at checkout: AMAVIP — 50% off your first monthly subscription, or AMAVIP_ANNUAL — 5% off your first year on annual.

Risks and mistakes that actually cost money

The wrong match

Worth repeating because I’ve yet to find another UK guide that covers it: the most expensive routine error in OA is matching a retail product to the wrong Amazon listing. Pack sizes, shades, bundles, regional variants, own-brand lookalikes. The symptoms are seductive — wrong matches usually look like the best deals on the sheet, because a 75ml price against a 100ml listing produces a fantastic fake ROI. Verify by barcode. Distrust anything that looks too good.

Gating, IP complaints and account health

Three related problems.

• Gating: Amazon restricts categories and brands, and the standard unlock is invoices from an authorised distributor or wholesaler — typically 10, 50 or 100+ units per product depending on the brand, dated recently, with your details matching Seller Central exactly. And here’s the catch for arbitrage sellers: receipts from the shops you actually source from won’t ungate you — I watch beginners find this out the hard way.
• IP complaints: brand owners can file complaints that take your listing down even when your goods are genuine; don’t ignore them, keep proof of purchase, and avoid brands with a known enforcement history.
• Suspension risk: “inauthentic” complaints can trigger demands for supply-chain invoices, and Amazon usually throws retail receipts out against that standard — I’ve watched it happen. Keep every receipt and order confirmation anyway, respond to performance notifications promptly, and treat complaint-prone brands as not worth the margin.

My ungating help exists because this whole area is where I watch beginners get stuck most often.

Overbuying a good deal

A profitable deal for 10 units is not automatically a profitable deal for 100. Deep buys concentrate risk in one listing’s price stability — and if the deal came from a shared list, everyone else went deep too. Buy in tranches; let the first batch sell before committing the rest.

Trusting stale information

This niche is full of ranking content that hasn’t been touched in years — retailer lists naming dead chains, fee guides citing superseded rates, “2023 tips” pages still on page one. Anchor on primary sources for anything with a number in it: GOV.UK for VAT, Amazon’s own pages for fees. I track fee and VAT changes on the blog as they happen, and I’ve dated everything in this guide to 2026 sources for exactly that reason.

Online arbitrage UK: FAQ

Is online arbitrage legal in the UK?

Yes — I checked this properly when I started. Once a brand puts a genuine product on the market, it generally can’t prevent its resale in unchanged condition — the UK’s exhaustion-of-rights principle. Legal isn’t the same as friction-free, though: Amazon’s own policies (gating, invoice requests, IP complaint handling) are a separate contractual layer, and that’s where the practical difficulties live.

Full answer here.

Is it still worth doing in 2026?

Yes — if you work the numbers rather than treating it as passive income. It’s still one of the lowest-cost entries into e-commerce in the UK. Margins are tighter than the 2020–22 era and competition has grown, so it rewards careful number-checking. Be sceptical of precise profit claims in either direction: most come from businesses with something to sell you — including, to be fair, me.

How much money do I need to start?

£500 minimum. Anyone telling you £200 is setting you up to stall — you’ll have it all tied up in stock with nothing left to move with. £1,000 is where it gets comfortable. On top of the stock pot: £25/month + VAT for the Professional selling plan and optionally £30–£100/month of tooling. The Individual plan at £0.75 per item exists for testing the water, but a small budget mostly limits how many lines you can run at once.

Full answer here.

Do I need a limited company?

No. Amazon accepts sole traders, and most people I see start that way for simpler reporting. You must register with HMRC once gross trading income passes the £1,000 trading allowance (Self Assessment registration by 5 October after the relevant tax year). A limited company adds liability protection and can be more tax-efficient at higher profits; incorporate later, once the numbers justify the admin.

When do I have to register for VAT?

When taxable turnover exceeds £90,000 in any rolling 12-month period — or immediately if you expect to cross it in the next 30 days alone. Remember it’s turnover across all your channels combined, not profit, and the application deadline is 30 days after the end of the month you crossed it.

Full answer here.

Can I do it part-time?

Yes — it’s the natural part-time model, since sourcing happens online at any hour and FBA handles fulfilment and customer service. Plan for around 10 hours a week when starting; that’s what I see work. It’s also the honest argument for outsourcing the finding step, whether to software or a leads service like mine.

What’s the single biggest beginner mistake?

Buying on the retail price and the Amazon price alone. Every loss I see traces back to a skipped verification step: the match wasn’t checked by barcode, the Keepa history wasn’t read, the fees and VAT weren’t fully priced, or the eligibility wasn’t confirmed before the stock was bought. The workflow above is seven steps because all seven earn their place.

Where to go from here