A supermarket offer is useful only if it beats the unit price

Before shopping, check what is already in the cupboards, fridge and freezer, plan meals and set a budget. The Consumer Council recommends a shopping list to reduce unnecessary purchases.

At the shelf, compare the price per unit rather than relying on the size of an offer label. Own-brand alternatives and loose produce can be worth checking, but value depends on the quantity you will actually use.

A promotion can increase the bill if it encourages an extra purchase. Compare equivalent quantities and ask whether the item belongs in the planned shop before treating a multibuy or special display as a saving.