Yes, be sure to watch your local sportsman's classifieds. Here in Florida we have several online sprtsman's classified that often have some very good deals on lightly used AR's. I believe Georgia has the same rules allowing face-to-face sale of firearms between private individuals.
With the continued downturn in the economy many folks are having to part with their guns just to survive. Sad as it is, for the potential gun buyer it can offer the opportunity to obtain some very quality weapons at great prices.
Even if you found a more heavily used Colt for instance at a good price, you can easily strip it down and rebuild it with new parts of your liking. The system is completely modular and parts are widely available and interchangable.
Pawn Shops and Gun Stores may also provide an opportunity for buying a used AR, but their prices will obviously be higher than you'll find in a private deal.
Good luck on your quest!
If you want a fairly decent new AR, DelTon has nice new ones available for $750 that will serve you well. This price does not include shipping or FFL transfer fee.