KSS MultiCalc is an app for Windows Phone 7 that has several calculators.

1. Best Price Finder - Allows you to compare the price of two products at a store to determine which product is a better value for your money.
2. Tip Calculator - Helps you determine how much the total bill and tip amount should be for a service.
3. Miles/Kilometers - Converts miles to kilometers and kilometers to miles.
4. Celsius/Fahrenheit - Converts Celsius to Fahrenheit and Fahrenheit to Celsius.

If you own a Windows Phone 7, or Zune software, you can find the app there.  You may also be able to find it on AppsFuze.