With this app of the day, you can leave your wallet at home while shopping. Pay With Square lets you add a credit card to the app and offers a directory list of participating stores. When you go shopping, open up a tab at the store with your phone, pick out your items, and when you get to the register just tell the cashier your name. They will confirm your identity looking at your picture that shows up at the register, to make sure it's you, you get your receipt and go.
Pay With Square is free to download and is available on the iPhone and Android.