stranger-danger

This may be a dumb question, but I'm curious. I havent actually played dayz yet but Ive been waiting for the standaone to come out for over a year. I've done some research and I'm willing to purchase the alpha version to play as well as assist in further development of the game. My only concern (and actual question) is that if I was to purchase the alpha version now while it is thirty bucks, will I have to also purchase the beta and final product separately later on or will I not have to re-purchase it but instead just have to deal with tons of patches and whatnot while the alpha develops into the final product? Does that make sense?

awesome thanks for the information, it was all really helpful.