According to the PlayStation Blog, PlayStation Plus subscribers will receive Stacking as a free download the day it arrives on the PlayStation Store; February 8. That's right, if you pay for Sony's extended PlayStation Network service then the entire game is yours at no additional cost.
While the wording on the PlayStation Blog might sound like Stacking will only be free for the first day it's available, a PlayStation rep confirmed to Shacknews that the game will be made available for free for the entire month of February. Like other free bonuses available to PlayStation plus subscribers, the game will not longer be available to play once a "Plus" subscription has expired.
Non-PlayStation Plus subscribers can nab Stacking on the PlayStation Store for $15. Stacking will also be available on the Xbox Live Arcade--albeit a day later on February 9--for 1200MS Points ($15).