aspenleaf.com has a GPS program with unlimited FREE updates for life for something like $49 now. I have this and it works pretty well, plus saving the money on the updates is great. They are working on a moving map version which will also be a FREE upgrade once it has finished testing and production runs. They even have site links to help buy the PDA and GPS unit as cheap as possible. I paid $250 for the complete setup, and i will always take the FREE upgrades they have.
I think that is still the website, if not it will at least have a link to get to the correct part of the site.
One drawback is, do NOT buy the PDA with little memory. GPS systems take a lot of space and you will do best with one that has upwards of 16MB if you can get it. MY 2MB PDA barely holds the info, and allows nothig else to be on there because of space problems. Soon i will be going to the newer iPAQ PDA with the newer GPS system as advertised in SPorty's, but i WILL NOT buy it from them... they over charge so much for their stuff.