Use your shopping trips as opportunities to teach your child- about colors, for example: “This can is red; that box is blue; that jar has a yellow label.” Your child will recognize the corn flakes box that she sees at breakfast every morning and will soon understand what the words mean, so that from quite an early age, say, 18 months, you can say to her, “Can you see the corn flakes? Now I wonder where the jam is.”
Word recognition can be encouraged by associating the contents of a carton or can with things that your child actually eats at home. For example, if she drinks juice regularly, you only have to take the carton of the brand she sees every day from the shelf and ask “What does this word say?” for her to respond with “juice,” because she has learned from experienced that juice is what comes out of that carton. All my children began to read food labels before they read anything else.
An older child will also learn about the act of shopping itself, and the decision-making and choosing that are involved. You can introduce her to the value of money and to continuing, and to some degree you can teach her about sociability and manners, because she will quickly learn the justice of allowing other people to get to the shelves when she has a great interest in doing so herself.