As a suggestion, how about starting a non-RPG "Share the Love" circle at Amazon?
Basically, if someone decides to buy the book for the discussion group, they post a thread to that purpose, people send emails asking to be included in the list, and so on. The people who end up buying the books will get a 10% discount (which, apparently, sticks around; at least, I'm STILL getting a 10% discount from when I bought the 3.5 rulebooks...). The person starting the list gets some bonus per person who actually buys (but, since this is in the books/movie forum, it won't be as big an audience).
And so on.
Anyway, just a suggestion.