A good deal is a useful purchase at a competitive total cost. A large saving badge is only a starting point: it does not tell you whether you need the item, whether the comparison price is meaningful or whether another seller charges less.
Use the six checks below before ordering. The examples are hypothetical and explain the method; they are not live offers.
1. Decide what you would buy without the discount
Write down the job the purchase must do and the maximum you want to spend. That gives you a reference point independent of the retailer’s promotion.
If you intended to replace a broken kettle, compare suitable kettles. If you had no reason to buy one, a lower price still creates spending rather than a saving against your plan. An upgrade can be worthwhile, but name the benefit you are paying for.
2. Match the exact item
Compare model number, size, colour, quantity, included accessories and condition. A similar title can hide a different product: a camera-only listing is not the same as a complete monitor kit, and a refurbished phone needs a separate comparison from a new one.
For groceries and toiletries, check weight or volume as well as the pack count. For electrical goods, confirm that the seller supplies the appropriate UK version and power accessories.
3. Compare the amount you will actually pay
| Hypothetical offer | Item price | Delivery | Payable total |
|---|---|---|---|
| Shop A | £40 | £5 | £45 |
| Shop B | £43 | £0 | £43 |
Shop B costs £2 less despite the higher item price. Add compulsory fees and necessary accessories, then deduct discounts that actually apply at checkout. Keep unconfirmed cashback separate from the amount you must pay.
4. Check the price context
Look at other credible retailers and any available price history for the exact variant. A crossed-out price or recommended retail price is not proof that other shoppers regularly paid it.
A hypothetical item reduced from £100 to £50 is advertised as 50% off. If comparable sellers currently charge £45 delivered, the £50 offer is still £5 dearer. The calculation of the discount and the competitiveness of the purchase are different questions.
Our price-history guide explains what to check when a history tool has gaps or combines variants.
5. Check quantity and running costs
For consumables, compare the same unit: per litre, per kilogram, per head or another relevant measure. The CMA’s unit-pricing guide explains how these labels help compare pack sizes.
Then ask how much you will use. A larger pack at a lower unit price can still increase spending if part of it goes unused. For appliances, include the repeat purchases needed for ownership, such as compatible brush heads or printer supplies.
6. Check the seller and the terms that affect value
Identify who sells the item, particularly on a marketplace. Read delivery times, return conditions and the product’s condition description. A slower delivery or different warranty arrangement may be acceptable, but make the trade-off deliberately.
Citizens Advice advises researching unfamiliar sellers and being cautious about unusually large discounts. Check more than a single review or an advert that led you to the shop.
A quick decision rule
- Buy now: you need the item, the exact version suits you and its total cost compares well.
- Keep checking: the seller, condition, pack contents or price comparison is unclear.
- Leave it: the main reason to buy is the discount badge, or the purchase would displace something more useful in your budget.
Does the cheapest price always win?
No. You might reasonably pay more for a needed delivery date, easier collection or a condition you prefer. Write the premium as an amount: “I am paying £4 extra for this delivery option” is clearer than assuming one retailer is automatically better value.
For related methods, see our unit-price guide, discount-code guide and bulk-buying guide.
Figures and limitations
Source guidance checked 25 October 2026. All monetary examples above are illustrative.
Give the saving a cash limit
Write the maximum delivered price you would accept before opening the sale page. Include necessary accessories in that limit. If a hypothetical £40 purchase needs a £12 part to do the intended job, compare £52 with the complete alternative.
If the offer exceeds your limit, decide whether a specific added benefit justifies revising it. The retailer’s crossed-out price is not a reason to increase the budget on its own.
