i highly recommend BOOK-OFF as well.
i don't go to the Los Angeles one, but from my experience at the Costa Mesa/Orange County one, you should DEFINITELY go. it's very cheap for used CDs. i even got some new, un-opened ones for less than $10.
i've seen CD albums go as low as $3 (i got Hikki's "First Love" album for that price). and singles as low as $1.
