didn't the developers state that the game would be free and payments are only for hats?
i just got 10 gifts of DOTA2 and declined them all >

because fuck you

Still in Beta though, so invites were/are the only way to get in.
Before there were mass invites, people were willing to pay up to $15 to grab one.
Same with the CS:GO Beta Invites. Gave one away, and traded another for $35 worth of games.
Invites? ARE YOU SERIOUS??? I GOT THIS GAME BY DOING SOME MOTHAFOOKING SURVEYS BY STEAM!!!