Does what you need
This ap is a good option to quickly calculate percentage discounts on single items and purchases while you're out shopping. It loads quickly, and has a simple interface using the number keypad (instead of the numbers and symbols section of the regular keyboard). It allows you to choose any value as a percentage, and immediately displays both the discount and the final sale price. It also allows you to add multiple items to the equation, and will allow you to use one percentage value for the whole purchase amount, or different percentages for different items (e.g. 50% for one item, and 10% off another). If you hit 'add' accidentally to add another item, you can delete it from the list by swiping left to show the Delete button. It is ad supported with both a small ad visible during use, and a pop up. The smaller ad is fairly unobstrusive. The app allows sharing to Facebook, Twitter and email, plus allows you to 'add to reading list', 'copy' and 'print'. My main improvement would be to place the dollar sign in the correct position in the Discount and Total fields.
