Price comparison guide: how to check you are paying less

Last checked November 2026. Offers and rules change: confirm with the provider before you rely on them.

Comparing prices means checking what the same thing costs in several places before you buy, and the quickest way is to compare like with like: the unit price on a supermarket shelf, the exact model number for goods, and the same level of cover for insurance and bills.

In the supermarket: read the small print on the shelf label

Every shelf label shows two prices. The big one is what you pay. The small one is the unit price: the cost per 100g, per kilogram, per litre or per item. The unit price is the only fair way to compare a 400g tin with a 300g one, or a branded pack with the shop's own.

Bigger is not always cheaper. Check the unit price on the large pack against the small one. It often is better value, but not always, and it is no saving if half goes off.
Look up and down. The dearest brands sit at eye level. Own-brand and value ranges are usually on the lower shelves.
Check loose against packed. Loose fruit and vegetables are priced per kilogram, bagged ones often per pack, so use the unit price to compare.
Multi-buy offers only save money if you will use the extra.
Member prices can make a real difference; see loyalty cards compared.

Tip: If the unit prices on two labels use different measures, one per 100g and one per kilogram, multiply the 100g price by ten to compare. A small magnifier in your bag helps with tiny label print; see reading glasses and magnifiers.

For household goods: compare the exact model

For a kettle, a television or a vacuum cleaner, the trick is the model number, a mix of letters and figures printed on the box and in the description. Two products that look identical can differ in small ways, and retailers sometimes stock their own variation.

Decide what you need first, before looking at prices. Our buying guides, such as lightweight vacuum cleaners, list the features that matter.
Note the exact model number of the one you like.
Type the model number into a search engine such as Google and choose the "Shopping" view, or use a price comparison website. Either will list retailers and their prices.
Add delivery. A lower price with a delivery charge can cost more than a higher price delivered free, and some shops offer free click and collect.
Check who is selling. If the cheapest price is from a shop you have never heard of, run the checks in online shopping safety before going further.
Compare the guarantee. Some retailers include a longer guarantee at no extra cost, which can be worth more than a small saving.

Is the sale price a real saving?

A "was" price can be flattering. What matters is the price today against other shops today. Price-history tools, offered by some comparison sites, show what an item has sold for over recent months, which is a good test of a Black Friday or January "deal". Our seasonal sales calendar shows when different goods typically come down.

Price promises

Some retailers say they will match a competitor's lower price. Terms vary: usually the item must be the identical model, in stock, and sold by a named list of rivals. If you prefer a particular shop for its service, it costs nothing to ask.

For bills and insurance: use comparison websites with care

Comparison websites for car and home insurance, broadband and mobile contracts collect quotations from many firms after you answer one set of questions. They are free to use because the firms pay them a commission when you buy.

No single site covers every company. Trying two sites gives a fuller picture, and a few well-known insurers do not appear on any of them, so you have to go to those direct.
Do not sort by price alone. Check the excess (the part of any insurance claim you pay yourself), the level of cover, the contract length and what the price will be after any introductory period.
The order of results may include sponsored listings. Look for the option to sort by price or by total cost.
Use the quotation to haggle. A cheaper quote in your hand is the strongest thing you can bring to a phone call with your current provider; see our haggling guide.
For energy, broadband and phones, look for comparison services accredited by the regulators, Ofgem and Ofcom, which have to meet standards on accuracy and fairness.

Watch out: If you receive certain benefits, a broadband social tariff may be cheaper than anything a comparison site shows, because these tariffs are often not listed. See broadband social tariffs.

Without the internet

You can compare prices perfectly well without going online:

ring two or three shops and ask the price of the exact model
pick up supermarket leaflets and free magazines, which list the current offers
ask at your local library, where staff can often help you use a computer to look something up
ask a relative to check a price for you; it takes them a minute

Do not forget the discounts

The lowest shelf price is not always the lowest price you can pay. A weekday over-60s discount, a loyalty price or a voucher code can beat it. See high street discounts for over-60s and cashback and voucher codes, or try the discount finder.

Common questions

Are price comparison websites free?

Yes. They earn a fee from the retailer or provider when you buy through them. You should not be asked to pay anything.

Is the cheapest always the best choice?

No. A slightly dearer retailer with good service, a UK address, easy returns and a longer guarantee is often better value, especially for large items.

Why does the same thing cost different amounts in different branches?

Many chains charge more in small convenience branches than in their large supermarkets, and offers can vary by store. If you can get to a larger branch, or have the shopping delivered from one, you will usually pay less.

Do comparison sites show every deal?

No. Some firms choose not to be listed, and special tariffs such as social tariffs are often missing. Treat a comparison site as a strong starting point rather than the last word.