According to a post on Steam, the game will drop to $60 when it goes into beta in September.
Although the idea of paying extra to help test an unfinished game may rankle, if you think about the game in a crowd-funding context it makes more sense. Backers forked out extra for the privelege of trying the game ahead of everyone else, and if developer Uber Entertainment let general punters in at no additional cost it wouldn't be very fair to those who helped pay for the game's development.
Additionally, buying into the alpha nets you the Galactic Edition with all add-ons, whereas the beta price will include just the standard edition.
The full game is due to launch in December.