Spend your money on flying training. Gizmos do not improve your flying in fact they probably do the opposite. Fly speed and time, look out of the window and use good old fashioned nav. So my advice is buy a better whizz wheel and spend more time flying. That will make you better pilot.
but when doing time building, with a gps you will feel safer knowing where you are in case you get lost.
How did we manage eh????
Getting lost is part of learning too you know.