The way it work is around 12PM tomorrow, GameStop will post an update to their Facebook and Twitter with a special link. If you are one of the first 100 to select that link you will see the game in your cart and a coupon code will be pre-populated for the discount mentioned above. If you’re not one of the first 100, you will see a better luck next time type message. Keep in mind it’s the first 100 people on Facebook and the first 100 on Twitter so you have double the chances. (Either that or it’s 50 FB and 50 Twitter)
The current price of the game is $14.99 so it should be around $3.74.
Not sure what type of DRM it uses, but keep in mind it’s an Ubisoft game.