Another Amazon app, Flow is Price Check with a twist: It doesn't require you to find the bar code. Using technology similar to Google's "Goggles," you can simply point your camera at the cover of a book, album, game or DVD and Amazon will try to identify the product on sight. Like Price Check, it will then pull up the Amazon price and allow you to visit the site to make your purchase there.
If nothing else, Flow wins on "wow" factor -- the image recognition technology is impressive, and the augmented reality interface means that you can simply point the camera at a product and its Amazon price will be superimposed on your field of view. (We're imagining a future where such an app can be used with Google's Project Glass, allowing you to simply look at a product and see better prices – but maybe we're getting ahead of ourselves.)
Of course, the image recognition technology isn't foolproof, so you're always going to get better results from a bar code scan. But if you're self-conscious about openly scanning bar codes at the store, or you simply want a taste of the future, give Flow a try.