As I was browsing through Amazon, I came across this deal that seems to be extremely cheap. It is 90% off, and i'm quite sure i've seen this game at $5.00 USD even on sale before.
A little bit about the game:
The Aliens are perfect killing machines, the nightmares of the galaxy. Our only hope for survival is the ultimate in military force. Are you ready to sign up with the Colonial Marines? 17 weeks after losing contact with Hadley’s Hope, a new team of Colonial Marines returns to LV-426. The rescue mission becomes a battle for survival against new dangers, new enemies and new species of Xenomorphs. Developed by Gearbox, the critically acclaimed developers of Borderlands and Brothers In Arms, Aliens: Colonial Marines is the ultimate action/horror first-person shooter.
NOTE: This is a Steam Redeemable Key from Amazon.
Please enjoy the game! Hope this post finds you well.
Might be a challenge: http://www.metacritic.com/game/pc/aliens-colonial-marines