The two places i shop are:
Price Owl
http://www.priceowl.com
- This place will let you search for any kind of book (not just game
books!!) and then find the best prices from a bunch of different
sources.(Amazon, Barnes and Noble, BooksAMillion, Bigger Books,
ECampus, Buy.com, Half.com, Walmart, Overstock.com, Half Price
Computer Books, Alibris, and BookCloseOuts). You can usually find
great deals on new or used (whichever your preference) game books at
as much as half off the new books! GREAT website. Only has a limited selection of the more well known game companies, though.
The other place is:
FRP Games
http://www.frpgames.com
-This is pretty much an rpg/minatures online game store that has all
the newer stuff (no real old game books or used stuff) where
everything is 20% off cover price. You won't get quite the deals
that you will at priceowl, but you're more likely to be able to buy
any game book out there (from whatever game company) that you're
looking for. You can pay be check, money order, credit card, or
paypal. So anyone can buy from them.