Check out Wal-Mart, a friend of mine scored a Magellan Explorer 200 for $74 bucks. That sounded like one heck of a deal. Personally myself all I have used is Garmin.
Be a little careful about buying a used one, I bought a used Garmin etrax vista off the forums, and it must of taken a heck of a smack, ever once in while when it gets bump while caching it shuts off. To get it fixed it would cost me $140 bucks, for that I could of bought a new one. Just an FYI.