Check this out! Great alternative CD's you don't usually find in used shops, and most for $5-6 with cheap shipping:
http://www.summervillain.com/cd.php
I picked up a few, this guy is totally on the level, real nice guy.
Some discs have small initials written in marked on the disc, or a small paper 'property of' sticker on the back tray card, but the discs are usually in excellent shape (you can ask if you're concerned).