Also, consider the earning potential. If you were to have a feature that gave users the option to anonymously upload barcode, gps location, and price to your centralized server, you would have quite a valuable database of shelf prices that don't tend to appear online.

You would have so much potential with this. Users could get instant feedback of not just online prices, but other local brick and mortar prices. And you could perhaps devote a part of the screen to ads that are similar to the scanned product (ad revenue could compensate mbarcode developers).