The simplest GPS handhelds to operate are Garmins. One I would recommend would be an ETrex 10, which runs $119.99. This is as basic as you can get while having waypoint and tracking features, but doesn't accept maps. If you want more info, shoot me a PM. I also work at Bass Pro in the Marine Dept., where we have many units on display--you can check them out and see what suits you best.

-Matt