Grocery savings: unit prices, multibuys and loyalty prices

Shops usually show a unit price, such as price per 100g, per kilo, per litre or per item. Use it to compare different sizes and brands. A larger pack is often cheaper per unit, but not always.

"3 for 2" or "buy two" offers only save money if you would use all the items. Check the total, and whether each item is cheaper than the single price elsewhere in the shop.

Some prices are only available with a store loyalty card or app. Check whether the card is free, and whether you will actually use it before choosing a shop just for its member prices.

Before stocking up on a deal, check the use-by or best-before date and whether you can freeze the item. A cheap price is no saving if the food goes to waste.

Check your cupboards and freezer first, and write a short list. Offers are most useful on items you already buy regularly.

Some promotions end quickly or vary between stores and online. Confirm the price at the till or in your basket before you pay.

For online shopping, add delivery charges, minimum basket amounts and substitution rules to the total.

• Unit price compared
• Multibuy total worked out
• Loyalty card or app needed
• Use-by and best-before dates
• What you already have at home
• Offer end date
• Delivery or minimum spend

Filbri is a discovery site. Each supermarket or grocer sets its own prices, offers and terms. There are no partner links on this page.