We have a store in town - the Book Heaven; "where good books go after they've been read." She will give you IN STORE credit of 50% the original purchase price of your book. Then when you go to buy a book (priced at 50% off original) you have to pay 25% the cost and the other 25% in credits.
I also have Paperback Swap. With this one I have a wish list, I post books I have to send out and I can print the wrapper right at the site. I only have to put 1.59 postage on a book to send it out.
How would you all decide where to send your books????? Though I really want to keep them all....it doesn't work well with moving every 3 years so I tend to pass on the fiction mysteries..... I AM keeping Penn Dutch Inn, and Rex Stout books. LOL