Good plan, chairboy. I have a couple friends who use simple handheld GPS units that aren't for aviation but work ok...to a point.
They don't have MOA's, Navaids, Airspace, TFRs and what not programmed, and the pilot III also has airport information loaded into it. Frequencies, runway lengths and so on. If you plan on doing some serious X/C flying after your private ticket, the $500 investment is money well spent on an aviation GPS.