Does anyone have any tips for getting a good price on new/used programming-related books? I've looked at some of the more popular books (like DDD and GoF), and even used they can be pretty pricey. I'm not saying they aren't worth it, but I feel like there might be a more focused book store or exchange or something just for devs and/or IT professionals that I just don't know about.
Any tips at all would be appreciated.