This seems to depend upon the author/publisher more than anything else. It also seems to heavily depend upon the type of book (e.g. DRM free computer and scienc

This seems to depend upon the author/publisher more than anything else. It also seems to heavily depend upon the type of book (e.g. DRM free computer and science fiction books seem to be the most common). Even when you do find a store that sells DRM free ebooks, you have to be careful about buying books that are labelled as such. Kindle is probably not the best choice for DRM free books since ePub and PDF are the dominant formats (outside of Amazon).