I suggest looking on Ebay. Many people sell items that are new in the package that would be reliable. Choose carefully, but you could probably find a good deal. If not there, try Amazon.
Microsoft sells one with Microsoft Streets and Trips http://www.amazon.com/s/ref=nb_ss_gw/002-4322208-9088821?url=search-alias%3Daps&field-keywords=microsoft+gps but you have to run it off of a laptop.
wait until the day after Christmas, you'll find a killer deal.
check your cell phone, you might already have one! my Nextel has GPS that you can get software for on your laptop/etc.
