Well, the Anatomical Chart Company used to have some screamin' deals on less than perfect skeletons, skulls, and bones by the pound. http://anatomical.com/bcategory.asp?c=7 The deals don't seem to be as great as they once were, though. There's also http://www.boneyardbargains.ca/mainpage1.html, which I think is not actually related to Anatomical Chart, but they do seem to have some good prices on skeletal parts. I think the prices are Canadian, too.
Anatomical Chart used to have a section called Bucky's Boneyard or something similar, but I think their old version was cheaper and looked better. Oh, well.