Aldi and Lidl are often the cheapest, but they don't sell their full range online, so their prices are harder to get. We use prices from shoppers' receipts to cover them.
To help: open the app, tap Scan receipt and take a clear photo of a till receipt from any supermarket. We read the items and prices, a moderator checks them, and they're used (anonymously) to keep in-store prices accurate. We never store card details – receipts are only used for the item lines and prices.