For a little more than $120 you could get the following device -
http://www.geeks.com/details.asp?invtid=GPT-801&cpc=SCH ($54.99) - which I hear from colleagues in the Microsoft Windows Mobile team like for a general purpose, inexpensive receiver with the SiRF III chipset and then buy a mapping program.
a friend who is a geocaching junky loves Mapopolis
(http://www.mapopolis.com), which I hear is a great mapping app and works very nicely with Windows Mobile devices - $99 buys you maps for all of North America ($124 for Western Europe) and unlimited free updates and free maps for that region of the world for one year.
One thing to keep in mind though is that this geocaching buddy of mine mentioned...the GPS experience is only as good as the mapping software in partnershp with the GPS device. If the maps don't provide accurate information because the map simply doesn't havee the updated or detailed information, then the GPS device itself is a moot variable and the utility is diminished. You shouldn't have a problem getting a very good device for under $120...depending on your needs because there are some very cool devices out there for hundreds of dollars. However, getting a device and a good mapping program all for under $120 will take some effort...they exist, but you need to look around.
Again, the above is completely dependant on what you're really looking for. If you plan to use the device and maps regularly, then it might be worth spending a little more money to get exactly what you want and need so you're not always frustrated. However, if this an occassional hobby type effort then starting off small and working your way into something more serious is definately the way to go, IMHO. For instance, the $54 device mentioned above paired with Windows Live Maps or Google Maps si likely a great place to start. If you like the utility then invest in a good mapping app.
Hope that helps.
--Phil