All you pay for is shipping of your items.
You list the books, CDs, DVDs, and video games that you want to get rid of and the books, CDs, DVDs and video games that you want and swaptree does the rest.
Swaptree will show you all of the items that you can receive for your items. Clicking on a "GET NOW" link next to an item will show more information about both the item and the trader you will be receiving the item from.
If you decide that you want to initiate a trade for an item, then an e-mail will automatically be sent to the other parties in the transaction. If the other traders accept, the trade is completed and you will then be provided the shipping address where you need to ship your item.