How DealStacker works
The method behind the lowest stacked price.
The problem: the sticker price is rarely the real price
Most UK shoppers leave money on the table — not because they don’t look for discounts, but because the best discounts can be combined, and almost no one combines them correctly. A loyalty price, a voucher code, a discounted gift card and a cashback offer can all apply to the same purchase. Stack them in the right order and the real cost drops far below the advertised price.
DealStacker exists to do that maths for you. You search for a product; we work out the true cheapest way to buy it across UK retailers, and show you the bottom-line cash price after every discount has been applied.
Why order matters
Discounts are not commutative. A percentage cashback calculated on the price before a voucher is worth more than the same cashback calculated after it — and some discounts are applied to the ex-VAT balance, not the headline figure. Apply them in the wrong sequence and your estimate will be wrong. DealStacker uses a single fixed waterfall so every number is consistent and defensible:
- Base RRP — the retailer’s headline price, our starting point.
- Loyalty member price — an instant lower price unlocked by a scheme you belong to (e.g. a My John Lewis member price). Applied first because it changes the price every later step is calculated from.
- Voucher codes — fixed-amount codes first, then percentage codes, so the percentage works on the already-reduced figure.
- Gift-card discount — buying a retailer’s e-gift card below face value (a common, legitimate way to shave a few percent off any purchase).
- Cashback — affiliate or card-linked cashback, calculated on the correct (often ex-VAT) balance at this stage of the stack.
- Credit-card cashback — the final layer, a small percentage back on whatever you actually pay.
The result is the stacked price — the genuine cash you part with after everything is combined. It is the number we rank retailers by.
Cash now vs. value later — we never blur the two
Some “savings” aren’t money off today. Loyalty points — Nectar, Clubcard, Boots Advantage — are earned on a purchase and redeemed later. They have real value, but folding them into the headline price would overstate how cheap a deal actually is.
So DealStacker keeps them strictly separate. The stacked price is cash you pay. Points are shown alongside as deferred value (“+£x in points”), clearly labelled as earned, not discounted. You always know exactly what leaves your account today.
One engine, two places to use it
The same calculation engine powers both the website and the DealStacker Chrome extension, so the numbers always match.
- On the web — search a product and compare the stacked price across retailers before you decide where to buy.
- In the browser — already on a retailer’s product page? The extension reads the live price and runs the identical stack in place, confirming the deal and helping you apply any voucher at checkout.
Discover on the web, close the deal with the extension — two ends of one journey.
How we make money
DealStacker is free to use. When you click through to a retailer and buy, we may earn a commission through affiliate partnerships via the AWIN network. That commission is paid by the retailer and costs you nothing extra — and it never changes which deal we rank as cheapest. Our ranking is driven solely by the stacked cash price, not by what pays us most.
A note on our launch data
DealStacker is in early access. While we onboard live retail feeds, the product catalogue and some discount rates shown are illustrative examples, clearly labelled as such across the site. The stacking engine, the waterfall logic and the savings calculations are fully real — what’s being finalised is the live pricing that flows into them.
Questions? Read our privacy policy or get in touch at hello@deal-stacker.co.uk.