If you love to read like me and you haven't heard about Paperback Swap then you are missing out. This site is a very simple way to get new novels. It isn't just science fiction by any means but there are more than enough science fiction and fantasy novels to pick from.
How it works is that you list ten or more books of yours which you are willing to send to someone. You then get two free credits. Each time you mail a book to someone you get another credit. You can then use one credit to get a book from anyone else in the system.
Just like any used bookstore getting some authors stuff is more difficult than others, but I've gotten quite a few good books this way.
There are sites connected to this one who do CD's and DVD's as well.
If you like to read check it out here.