Nothing ruins a recent purchase quite like finding lower prices online as soon as you bring it home. With one of these barcode-scanning, price-crunching smartphone apps, that never has to happen again.
RedLaser
(http://cache.gawkerassets.com/assets/images/4/2010/12/500x_redlazzzzz.jpg)
A quick, relatively accurate barcode scanner from the company that provides the basic scanning functionality for many other apps on this list, including Amazon's, eBay's and FoodScanner's. Independent of any particular retailer or price aggregator (though now owned by eBay), RedLaser is free to search a variety of online sources for the best prices, which, combined with its best-in-group scanning ability, makes for a hugely useful app on any post-3G iPhone. Free, iPhone.
The Best Barcode Scanner Apps [Appbattle] (http://gizmodo.com/5713768/the-best-barcode-scanner-apps)