Around here we have a saying- Any quad that runs for under a grand is a pretty good deal. To that end, if you've been hankering to ride but funds are tight, we located a 1986 Suzuki Quadrunner LT125 that is said to run great for $500:

Weekly Used ATV Deal: Old School Suzuki LT125 on the Cheap - ATVConnection.com

These make for very good/ reliable beginner machines to get the wife or kids into the sport.