This week, Sony announced a new experiment in free-to-play gaming coming to the Playstation Network, in their most recent Blogcast podcast.
Killzone 3 Multiplayer will be available on PSN next week. This edition of the shooter spins off the multiplayer part of the game as a separate entity from the single-player campaign, bringing all of Killzone 3's multiplayer modes and maps, including a year's worth of DLC maps, to consoles for free. Developers Guerrilla Games explain that players have access to all multiplayer material until the level of Sergeant I before needing to pay $15 to unlock and continue leveling or gaining trophies.
Killzone 3 launched almost exactly a year ago, in February 2011. The Kotaku review at release called it a "colorful, wonderful, enthusiastic mess."