Here are a few options to consider.
RedLaser (Free; iOS, Android) - Need a quick price comparison while you're in the store? It can scan any product barcode using your smartphone's camera. Then it quickly looks up the product online. You'll instantly get prices from Google, eBay, Shopping.com and more! Don't worry about overpaying again.
http://redlaser.com/application/
PriceGrabber (Free; iOS, Android) - This app gives you the same functionality as the PriceGrabber website. Simply scan the barcode of a product with your phone's camera. PriceGrabber will display stores selling the scanned item, as well as the price at each location. (my favorite)
http://www.pricegrabber.com/ipad-iphone-android-app.php
ShopKick (Free; iOS, Android) – Earn money just for walking into a store. That's what Shopkick is all about. You can get points/kicks, just for entering Target, Best Buy, and dozens of other stores.
You can also receive points for scanning certain products. With the points earned you can exchange them for gift cards, movie tickets and other great rewards.
https://itunes.apple.com/app/id383298204?mt=8
