So right now on steam you can buy your way into the Alpha build of Arma 3 for 32 bucks (US).
Purchase Arma 3 Alpha now and receive the following:
I think this is kind of neat. allowing people a kind of ground floor access to the game. you get to in a way watch the game evolve over time as they fix bugs add new fetchers ect ect. I like this approach sure the game will break alot and be riddled with bugs, but you get to see a game in a state not a lot of publishers/developers would ever allow there game to be shown. (in theory) you would get to see it become a full retail game. This is not for everyone of course and i know more then a few people liked the idea of Arma in theory but the playing of it was another story all together. still a cool idea i think.