"There are not one, but two, apps that basically do the same thing: compare prices and save us money. Using the camera, you can "scan" the barcode of an item by snapping a picture. The app will then comparison shop for you. You can read online reviews and even create price alerts if the price drops. CompareEverywhere also lets you use the GPS to find nearby stores and then call them directly."
http://www.readwriteweb.com/archives/10_android_apps_we_will_actual.php