If your thinking of trying this out and seeing if you like it, get something like the Garmin Legend. The original (non-color screen). I think I've seen them at Dick's or other sporting good stores for around $100.00.
Or I looked around and found a brand new, not a referb, Garmin Legend CX, color screen for $129.99. Refebs at around $105.00.
It's a good trusty GPS.
The original Legend I used almost 4 years and over 700 Geocaching finds.
Both come with a very basic, not much detailed base map, as do most models. You can get TOPO maps which I use, and love, but the thing with the Legends is that they have a fixed amount of memory for the maps which is small. So if your going out of the area of your "standard" maps you would have to upload the new area maps.
Maybe find out if there are any Geocaching groups in your area. There's a group that meets every 4th Thursday of the month around me. Maybe you could find someone who has an old one around they could let you use for a bit a to make sure it works and then purchase it???