The Sacred Hearth

These days, most book stores do carry Pagan books in the New Age or Religion section, and if not there, the Mythology section. Larger stores, like Borders or Barnes & Noble will be able to order anything you can't find. Of course, amazon.com should have just about anything you could possibly want (and I appreciate your support by clicking the Amazon.com link). You may also wish to check out Pagan, Occult and New Age-Specific publishers such as Llewellyn and Endymion Press.

Used book stores aren't a good source for good Pagan books, because most Pagans, when they find a good book, are not going to give it up.