Users can sign up and place ads for both books and calculators.
If they are looking for a specific book, they will get automatically receive an e-mail when the books they want are posted on the site. The site is free to all users and derives its income from banner advertisements. Apparently, they are not allowed to link to any competition to the old on-campus bookstore. We personally believe that this is ridiculous since the Internet can't be stopped and we are providing a useful service to students. We have received dozens of e-mails thanking us for our site and telling us how much money students saved or how quickly students sell their books.