You do get a lot of stuff really cheap to start out with. But as you go on, you end up buying stuff just because it's there. Take the 10 CDs for a penny or whatever, fulfill your requirement and then quit.

I belong to BMG. It's pretty good; they don't have a lot of strings attached, and they will occassionally have really good deals, like unlimited 66% off all CDs. Also, if you haven't ordered from them in awhile, they'll give you even better deals (I got unlimited 75% off once because I hadn't ordered anything in over a year), and you can earn free CDs if you order a certain number of CDs. I find it really comes in handy around the holidays because you can get cheap gifts for people.