How does cashback work? A UK beginner’s guide

What is a cashback site?

A cashback site (or “cashback portal”) is a free website you visit before you shop online, instead of going straight to the retailer. You sign up, find the shop you want on the portal, click through to that retailer’s own website, and buy as you normally would. If the purchase goes through, some of what you spent comes back to you as cashback. The three biggest in the UK are TopCashback, Quidco and Rakuten — see our cashback sites guide for how they compare.

Where does the money actually come from?

This is the bit that makes cashback feel too good to be true, so it’s worth spelling out. Retailers already pay to acquire customers — that’s a normal marketing cost, whether it goes on adverts or on commission to whoever sent them the sale. A cashback portal is simply one of the places a retailer pays that commission when a shopper buys through it, and the portal shares part of it back with you rather than keeping all of it. Nobody’s giving money away — it’s marketing budget the retailer was going to spend anyway, redirected partly to you instead of to an advertiser. That’s why it’s free to use and not a trick.

The cashback journey, step by step

1. Sign up to a cashback site — it’s free.
2. Search for the retailer you want to buy from on the portal.
3. Click through to the retailer’s own website from the portal — not a separate search result, not a bookmark, the actual link the portal gives you.
4. Shop as normal: browse, add to basket, and check out on the retailer’s own site.
5. The retailer reports the sale back to the portal, and it starts to track.
6. Cashback appears in your account as pending.
7. Once the retailer’s own return window closes, it moves to confirmed and becomes payable.
8. Withdraw your balance — typically to your bank account, PayPal, or as a gift card, depending on the portal.

Why cashback sometimes doesn’t track

Occasionally a click doesn’t track, usually because something broke the chain between your click and your purchase — an ad blocker, another tab or coupon pop-up opened in between, or a voucher code the portal didn’t list itself. It’s almost always avoidable once you know what to watch for, and it’s fixable even when it happens. The full rundown, with the complete list of causes and how to claim missing cashback, is in why your cashback didn’t track — and how to fix it.

Stacking cashback with vouchers, gift cards and loyalty

Cashback doesn’t have to stand alone. On the same purchase you can often also use a voucher code, pay with a discounted gift card, and still collect your usual loyalty or member pricing — cashback is one layer of the stack, not a replacement for the others. The one thing worth checking first: at some retailers, paying by gift card is a common exclusion that can void the cashback, so it’s worth confirming which route actually pays out before you commit to it. The full method, in the right order, is in how to stack cashback, vouchers and gift cards.

Realistic expectations

Three things are worth knowing before your first cashback purchase. Rates vary: the same retailer can pay different amounts on different portals, and rates change week to week, so treat any figure you see as a snapshot rather than a promise. It’s not instant: expect pending, then confirmed, over weeks and sometimes months, not minutes. And it’s not guaranteed: most purchases track without any trouble, but a small share won’t, and even a missing-cashback claim isn’t always honoured, especially where an exclusion applied. None of that makes cashback not worth using — it just means treating it as a genuine but variable saving, not a fixed discount.

DealStacker checks live cashback rates as part of the wider stack, alongside vouchers, gift cards and loyalty pricing, so you don’t have to compare portals by hand. Search a product to see the current cashback route for it.

How we make money: DealStacker is free. When you click through to a retailer or cashback partner and buy, we may earn a commission. It costs you nothing extra and never changes which deal or portal we rank as best for you.

How cashback works — FAQ

Is cashback really free?

Yes. Joining and using a cashback site costs nothing, and the money comes out of the retailer's own marketing budget rather than out of your pocket. A couple of portals run an optional paid tier or take a small annual fee from what you earn, so it's worth checking a portal's own terms — but the cashback itself isn't a hidden charge or a trick.

How long does cashback take to pay out?

It shows as pending first, often within hours or days of your purchase, then moves to confirmed once the retailer's own return window closes — commonly a few weeks, sometimes a few months. Only confirmed cashback can be withdrawn. That wait is normal across every portal, not a sign anything's gone wrong.

Why didn't my cashback track?

Usually because something broke the trail between your click and your purchase — an ad blocker, another tab or coupon pop-up opened in between, or a voucher code the portal itself didn't list. It's almost always avoidable once you know what to watch for. See our full guide on why cashback doesn't track for the complete list of causes and how to claim missing cashback back.

Can I use cashback and a voucher code together?

Usually, yes — most codes and cashback stack fine on the same order. The exception is a code the cashback portal itself didn't list, which some retailers treat as grounds to void the cashback. Stick to codes shown on the portal's own retailer page, and see our stacking guide for how cashback, codes, gift cards and loyalty pricing fit together on one purchase.