Alan Wake is on sale for $14.99 (50% off) at GOG. In addition there’s a pre-order for the upcoming Alan Wake American Nightmare. Pre-order the game for $13.49 (25% off). If you buy it with the original Alan Wake you’ll get an additional 15% discount on the pre-order, which makes the game only $11.24. If you already own Alan Wake on GOG, you’ll also qualify for the 15% off bonus discount.
Alan Wake American Nightmare comes out May 22nd.
These are DRM free versions of the games.
Edit: Thanks to Mike S for sending in this deal!