Your only investment would be in gas & a GPS. I know you've been pointed to geocaching.com; they have device reviews there now (unless its for premium members only, but I dont think it is). That may help you decide which GPS. You CAN do it with even the most basic GPS and a little mapwork; I did about 45 finda with nothing more than a garmin 201, which is their wristop gps. that was simply a breadcrumb trail that I could follow, no maps, nothing. Just wanted to throw that out there for ya.