Just wanted to shamelessly plug a site that has helped me greatly in getting ahold of books that I want. The site works by mailing books you have and want to get rid of in trade for books you want to read. You mail your books to other members, those members notify the website of the book's arrival, and then you request books from other members. Its a cycle that works quite well despite some of the obvious concerns. I hear a lot of people wondering how everyone stays honest on the site. Well, for one thing, if you fail to notify the site after a month that your book has arrived so that the sender can be credited, the website seeks legal charges from the person. Ive never had a single book go unaccounted for and ive been a member for almost a year so far. Ive hunted down comment after comment on this site and I havent heard a single negative one, so I gotta say.... TRY IT!!!! Also, if you post 10 books, they give you a few freeby points to request random books and get you started. ANNND.... I get a freeby point for every person I refer to this site.... so you is doing me good things too if you sign up.
http://www.paperbackswap.com/index.php?n=2&r_by=cjkrythos as an added bonus, paperback has two sister sites for people who would like to trade music CDs and movies. The points are interchangeable between sites, so you can actually trade movies for cds or books for movies.
If you dont have books to trade, the way I go hunting for books to trade, or to get ahold of books I want for cheap, is to hit up these book sales.
http://www.booksalefinder.com/ Book sales in general are arranged by non profit organizations that are trying to raise money for various purposes. The organizations will sell donated books for prices of around 25-50 cents per paperback book and 50 cents to a dollar per hardbound book. Sometimes they charge more if the book is rare or autographed. To find a sale, go to the place, click on your state, and then go hunting for sales in your area. The site isnt very good at sorting stores that are close to you, so yes, you will end up with sales in cities youve never heard of, but that isnt always a problem, sometimes you might find a city with easy driving range that youve never heard of. Just do a quick browse on mapquest for info on the city and then wing it.
Also, book sales will often have discounts as the sale goes on, where they will mark everything half off, or on the last night, have a bag sale, where you are given a paper bag and told to fill it for a preset price for the whole bag, usually $3-5. Even if you cant find books that interest you, its also fun to find books that don't interest you so you can trade them in on paperbackswap for other books that DO interest you.
As a last option, go hunting for book stores in your area that take used books in trade. They all have different trade programs to earn credit, but its an excellent way to get a book you want because many of these stores have hard to find books that might be out of print. Find books at book sales for dirt cheap and then trade them in at book stores for a couple dollars. Also, avoid buying hardbound books for trade in credit. Many stores wont take HB books at all, or wont give you any good credit in the event that they do take them.
Good luck and happy hunting folks!!!!