Prices correct as of April 2016.
Do you use 1st and 2nd class stamps to send heavier letters? With Many Stamps it's easy, just tell it the cost, and it tells you the easiest way to reach that value using 1st and 2nd class stamps (see screenshots for details).
Check out my other apps if you often send postage, they will make your life easier.
Please email [email protected] if you have any questions or suggestions.