Want to save your bank account and the environment at the same time? Swap sites, where you trade your books and other media, can help.

Manually entering ISBN or UPC codes for every item you're willing to trade, however, does not make a lot of sense.

Swap.com is the first of the mainstream swap sites to solve this problem with an iPhone app that it released on Thursday. The new app allows you to simply scan the books, video games, movies and music that you want to trade. No manual entry necessary.

If you scan something you have and are willing to trade, the app shows you what the people with that item on their "want" lists are willing to trade. If you scan something in a store that you want, the app shows you how many of Swap.com's more than 1 million members have that item up for trade.

You can browse potential trades in a "Get Now" section at any time.

While it's possible to handle the entire trade process using the app, including paying Swap.com's fee using PayPal and emailing a printable shipping label to yourself, everything that is scanned also integrates with the desktop version of Swap.com.

This way, even users who have no intentions of browsing the app can use it as an easy item entry mechanism.