This app is useful when youre out to eat with a group of people. You enter the amount of the bill (before or after taxes, as you prefer; I usually tip on the total including tax) on a keypad. Then you select the percentage you want to tip and the number of people in the party. CheckPlease then tells you both the total amount of the tip per person and the total each person should pay. You can choose to round up the tip or not. I think the interface is terrific--everything is on one screen. If youre considering this app, you should be aware that a lot of the earlier complaints (particularly about the including tax/not including tax debate) have been addressed in later versions.
AppleRabbit7 about CheckPlease Lite - Tip Calculator