As an author of several books and a marketer I'm always looking for ways to promote my books without breaking the bank. Enter Goodreads.com - they offer several great ways to promote your books as authors. One of my most recent promotions is the book giveaway - see the information on the right.
So far this appears to be a deal for both author and readers. The cost is minimal and it gives the opportunity for readers to get the book they would like to read for free.