Had a similar happenign with different games. Bought them and the very next friday, they were on discount. Just my luck.

Anyway, I already had the game on my X360, although without any of the DLC, as I didn't enjoy the game very much. Then again, I only paid 10,- €, so I won't complain.
And I'm a bit curious about what happens in the DLC episodes. So, I grabbed the PC-Version yesterday and bought American Nightmare as well.

And a word of honesty, I really don't think Alan Wake was worth the full price. :/
The story is predictable, Alan probably the most unsympathic "hero" I've ever seen in a video game. And in this game, he's only topped by Agent Nightinggale, who's even worse.
Well, and the night sequences are boring.
Smart enemies and good graphics, but it feels like it's lacking soemthing very important. Like the polar opposite of Deadly Premonition.

A thing like this happened to my friend on Steam once. All his friends were crazy about Left 4 Dead 2 and encouraged him to get it too to join the fun. So he bought it and less than an hour later it was like 50 or 66% off. He messaged support and they actually gave him his money back.

But that's the only time I know of that someone's succeeded with it. :/

30 minutes in and I'm fucking glad I only paid 5 bucks. It's hilariously cheesy. But worth $5, I guess.