they sell them at auction pretty regular. They are pretty much like any other used cars. some are rust buckets, some are gems, totally depends.
I found mine on craigslist, seen a few more on there since. Mine wasnt a gem but it was a solid runner with some rust issues and a leaky oil pan. Got it for $1500, spent probably $3000 on it making it reliable (new starter, new alternators, new U-joints on the rear driveshaft, new brakes including bearings on the front spindles and quarter turn locking hubs). and a bunch of small nickle and dime stuff.
Basically you get what you pay for. A clean solid CUCV for $4000 that dosnt need any work, to me is worth it.
Also, keep in mind the different types of CUCV's, blazers, pickups, duallys, cab and chassis trucks. etc.