CplxCalPro, CCP, is the most powerful programmable graphicalcalculator for the palm platform.
While this calculator is not necessarily designed just to balance your checkbook, you could easily do so. CplxCalPro allows you to perform the most advanced calculations and function graphing without any programming. Instead of retyping the same equations with just a few different values you can create a little program. The manual contains a step-by-step tutorial with very easy to follow examples.
Use the Emulator to write your programs for CplxCalPro on a PC or MAC. After developing and testing your programs on the PC or MAC you can save the programs and hotsync them to your handheld. The user manual explains how to do this.