If your wanting just a cheap basic GPS you can hardly beat a Garmin Etrex. I have one and carry it any time I go into the woods. You can find them all over for under a hundred bucks. I think I picked mine up a few years ago for $90 or so at walmart.
If your wanting something a little better that has maps on it also then well just about any brand will work just fine. I just have always used garmin as they always worked good for me.