The author Joe Hill (son of Stephen King) is doing a great thing to promote the support of independent bookstores, both brick-and-mortar and online. He announced on his blog that he will draw a winner of a signed, slipcased edition of his new novel Gunpowder. All you have to do is to buy something at an independent bookstore and email him a copy of the receipt.
Subterranean Press liked the idea so much that they've added a list of limited editions as prizes, including a limited edition of Neil Gaiman's The Graveyard Book and two titles by Ray Bradbury, among other treasures.
He also does a quick FAQ about what constitutes an independent bookstore for his purposes.
I need to go out and read something by Joe Hill RIGHT NOW, based on this project alone.