Many retailers use electronic devices at their checkout counters to “scan” the UPC bar codes on each item to enable the cashier to total purchases faster, and help the store keep track of inventory.

Shoppers sometimes question whether the scanned prices are accurate.Consumers have certain legal rights in the event of inaccurate scanning. 

There are three conditions when a retailer must provide an item free of charge when it has scanned at a price higher than the posted price.

• The item must be a “consumer commodity.”This means a food, drug, device, cosmetic or other item produced for sale to retail stores, that gets "used up" or depleted, and is meant to be eventually replaced, such as: toothpaste, a loaf of bread, plastic wrap, or shampoo.  A broom, for example, is not a consumer commodity.
• The item must be on sale for a period of at least seven days, and offered in a publicly circulated advertisement, such as a newspaper circular.
• The consumer must ask that the inaccurately scanned item be provided to him or her free of charge.