Bushnell GPS BackTrack Marine Personal Locator
$53 to $72
Easiest to use, if all you want to do is find your way home, or back to the truck. It will set three waypoints, has one button operation, a one sheet instruction manuel that any 10 year old can operate within 3 minutes.
I have owned one of these units for about 4 years now, and it is accurate within 12" at a distance of over a mile.
You turn it on, let it find a satellite (requires about 30 seconds) and set your home point. Then you can turn it off, and know matter where you are within 999 miles, when you turn it back on, it will tell you how far you are from your home point, and the direction you go to get back.
It will require changing a AAA battery about every three years if used this way, or if you use it continuously you will need to change the battery about every 72 hours.