Though Just Cause 2 has been laughably cheap on PC, those of you without access may want to consider the still-budget-priced Just Cause 2: Ultimate Edition. It just became available on PlayStation Network for $24.99, which isn't much more than the asking price of the standard console game (also on PSN).
For the bump in price, you'll get the "Black Market Aerial Pack" and the "Black Market Boom Pack," in addition to eight individual downloadable items.
Prior to Saints Row: The Third, Just Cause 2 was my open-world sandbox of choice. Now, if only we could get the former to incorporate the latter's magical grappling hook and parachute.