<p>Avid readers horde books like a squirrel hordes nuts, but even the most relentless pack rats can run out of space. Garage sales and half-priced bookstores can be a great way to clean out those bookshelves, but you aren&#39;t going to get back the money you put into it.</p><p>That&#39;s where book swapping and book exchanges come into the picture. Instead of selling your book back for a fraction of the cost, you participate in a book exchange by mailing your book to someone who requests it and receiving your own request in the mail. Your old book finds a reader, and in return, you get a book to read.</p><p>Book exchange websites make the process of trading books easy. Most are free to use, and some even pay for the postage needed to exchange books.</p><h3>The Book Exchange is Good for the Environment</h3><p>One neat aspect of participating in a book exchange is the benefit to the environment. According to Greenpeace, one Canadian Spruce tree can produce only 24 books. This means with only a couple of dozen exchanges you will have saved a tree. Participating in a book exchange also saves on ink and leaves a smaller environmental footprint than printing a book.</p><h3>A List of Book Exchange Websites</h3><ul><li> <a href="http://www.swaptree.com/" data-component="link" data-source="inlineLink" data-type="externalLink" data-ordinal="1" rel="nofollow">Swaptree</a>. Trade books, music or video games.</li><li> <a href="http://whatsonmybookshelf.com/" data-component="link" data-source="inlineLink" data-type="externalLink" data-ordinal="2" rel="nofollow">WhatsOnMyBookshelf?</a>. Create book lists, categorize books by tag, meet people with similar interests and exchange books.</li><li>America&#39;s BookShelf. A full service book club that lets you share your books online.</li><li> <a href="http://www.bookcrossing.com/" data-component="link" data-source="inlineLink" data-type="externalLink" data-ordinal="3" rel="nofollow">BookCrossing</a>. Register your book and then set it free by leaving it on a park bench or in a gym allowing it to find a new owner and perhaps create a new book lover.</li><li> <a href="http://www.bookins.com/" data-component="link" data-source="inlineLink" data-type="externalLink" data-ordinal="4" rel="nofollow">Bookins</a>. Trade and exchange books and DvDs for just the cost of postage.</li><li> <a href="http://www.bookmooch.com/" data-component="link" data-source="inlineLink" data-type="externalLink" data-ordinal="5" rel="nofollow">BookMooch</a>. Mail your books to someone who wants them for points and then use your points to buy books from other users.</li><li> <a href="http://www.bookswim.com/" data-component="link" data-source="inlineLink" data-type="externalLink" data-ordinal="6" rel="nofollow">BookSwim</a>. The <a href="http://www.netflix.com/" data-component="link" data-source="inlineLink" data-type="externalLink" data-ordinal="7" rel="nofollow">Netflix</a> for books, BookSwim is a book rental service where you create a pool of books and have them mailed to you.</li><li> <a href="http://www.paperbackswap.com/" data-component="link" data-source="inlineLink" data-type="externalLink" data-ordinal="8" rel="nofollow">PaperBackSwap</a>. Exchange books with other readers for the price of postage.</li><li> <a href="http://www.readitswapit.co.uk/TheLibrary.aspx" data-component="link" data-source="inlineLink" data-type="externalLink" data-ordinal="9" rel="nofollow">Read It Swap It</a>. A UK-based book exchange service.</li></ul>