I rarely buy books new anymore since I've discovered I can get books in great quality for about half the price on ebay! There are also some old gems that you can't buy new anymore! Sometimes it takes a little hunting to find the good deals, but it is totally worth it! I suggest that if you're looking for books that you check out ebay first! Just to show some good deals I've gotten, here are my last few ebay purchases:
"Reshevksy Teaches Chess" by Samual Reshevysky
"The Complete Chess Player" by Fred Reinfeld
"Modern Ideas in Chess" by Richard Reti
"Chess Praxis" by Aaron Nimzovitch
"Modern Chess Miniatures" by Leonard Barden and Wolfgang Heidenfeld
"Morphy's Games of Chess" by Philip Sergeant and Fred Reinfeld
Hardcover "Modern Chess Openings 5th editon"
Hardcover "Modern Chess Openings 9th edition"
All of these books for $16.75 AFTER shipping! If thats not a steal then I don't know what is . The MCO 5th edition is the only one in dire condition, the rest are in fine shape!
"Nunn's Chess Openings" for $10 shipped!
"303 Tricky Chess Tactics" for $4 shipped!
As you can see you can get some great deals on ebay, so don't be afraid to give it a try!