It helps a lot if you have a smartphone and have coverage in the store - you can check if the book is in demand at:

http://www.paperbackswap.com/mobile/index.php (very cut down, useful search interface).

1. Goodwill and similar will have paperbacks for under 50c each, hardcovers $1 or so.

2. The Dollar Tree will usually have a bunch of hardcovers for $1.

3. Sometimes ISBNs are oversupplied here but in demand on bookmooch (specifically, The Kite Runner - 1594480001 - has 1000+ copies here and 107 wishers on bookmooch), so you can get 1 or 3 points (overseas - have to post from post office) for them and hopefully trade them someday for a book you want (bookmooch is hard to get high-demand titles on, though, so it's definitely inferior to PBS).

4. Tell yourself you really don't need that book and make it stick (that's the hardest one for me).

5. Check the bargain bazaar for credits; sometimes cheaper than buying a book and sending it off, but much less satisfying.

Don't forget the library.  I live in one county and work in another.  The library system in the county in which I work only has three small branches.  Because of limited space, they can only keep so many books on the shelves.  This is good for me as they sell almost new hardcovers for $0.25.  Last year they had a sale and were selling them for 2 for $0.25.  I got a bunch of wishlisted books that I wasn't interested in reading.  I posted them and mailed them out.  It was a great deal.

Man, all the thrift stores where I live are $1-$3 for most adult paperbacks (sometimes less for the really small ones), $4 for hardbacks, and $0.79+ for kids books.

Oddly enough, the library sales here (New Orleans) are more expensive than the Goodwill store - hardcovers run $2+ at the bi-yearly sales and paperbacks will run $1 +. However, these are not ex-library books; these are donated books, so you usually end up with a nearly-new book.

Walgreens occasionally have cheap hardcovers, too, but we're starting to get to bookcloseouts.com prices rather than buy and trade prices.

I have a thrift store I frequent that only charges 25 cents for paperbacks and 50 cents for hardbacks which is really cheap.  The problem lies in that I don't know which books are in demand.  I purchased a few books that I thought would be highly wishlisted.  Turns out a couple of them already had several copies in the system.  Wish there was a way to know which books are in demand.  It's a hit and miss thing with me.

Don't forget, if there is a book you want to read that's heavily wishlisted, you can generally get it faster by getting on the library list.  The way our library works is we get put in a line for the book we want and the line includes all libraries in the system.  So basically if my name comes up I get the next copy even if they have to ship it from another town.  I rarely wait more than a few weeks for a requested book.  The only downside.... no renewals allowed if someone else wants the book.  But a free read is a free read!

Edie