I don't know where all they have stores, but I'm in Dallas so they're at least in Texas.
I got $73 the last time I sold stuff and $48 the time before. They'll take any form of printed word plus music, DVDs, videos, records, 8 tracks, whatever. Current bestsellers get you the most money as far as books go, and my last two times I had a ton of DVDs in my stuff I sold. DVDs must be the real moneymakers.
I'll warn you though that if you just have a stack of musty paperbacks that were assigned reading in college, you'll probably only get $7 to $10 for 'em. But hey, that's $7 to $10 for books you were going to throw away anyway.