You're in the shop. Do I buy three of these for this price or two of those for that price? Which is the bargain? Just reach in your pocket, launch Bargain, enter the price and quantity for each item then tap Compare. Done!
The keyboard is always visible and robust error checking and a clean and effective interface make on-the-go comparisons a doddle. A quick 'shake to clear' starts again with a clean slate.
... and it's free!