The 2012 thriller adventure Alan Wake is currently on sale until 6pm BST on PC (unfortunately not on console), before being completely removed from sale forever.
You can pick it up at the below outlets:
You can also get Alan Wake's American Nightmare at a cheap price, too, as part of a bundle from GOG and Steam.
The reason for it being removed from sale is the expiry of the licensed songs in its soundtrack. This means that everywhere it is available will have to remove it from sale, including retail copies. American Nightmare is not affected.
If you already own Alan Wake, then game will stay in your library and continue to work for you.