Ok here is a must have app and you can get it for Android phones, iPhones or Blackberrys
It basically compairs prices for you with online prices VS retail shopping. How it works is you basically open up the app and it turns on your camera. You place the camera infront of the UPC scanner bars and it scans it for you. It will then search the internet and let you know what is the cheapest price for that item. Here is a example - I scanned my PogoPlug box
You can see the cheapest place to purchase it is Amazon for $99.99 or I can get it local for $139.99 basically saved $40.00 shopping online. I this app!
You can scan anything from a soda to huge plasma TV. Here is a video on it: