If you are looking for a used GPSr, I just joined the geocaching site, www.geocaching.com
that seems to be the "official" geocaching website. The site has forums, much like ours and one is called Garage Sale, where members can sell and buy used GPSrs. I don't think you need to be a member to view the forums. I saw some recent model Garmins and a few Magellans for sale.