Borderlands 2, one of 2012’s most critically acclaimed titles, is entering the Instant Game Collection today. Pick one of four new vault hunters (I went with Maya the Siren) and grab your randomly generated weapon, ‘cause a pesky psychopath called Handsome Jack is terrorizing the world of Pandora (but hey, he does it in style). Borderlands 2 excels in co-op mode, so team up with up some friends to explore the land. There are plenty of things to mow down for experience points and nothing feels better than a rare loot drop, plus you can customize your character to dish out more damage or provide support for you & your friends. You can take advantage of all these PS Plus benefits after PlayStation Store updates later today. Source - PS Blog
It's not truly free. You can only play it as long as your a playstation plus member. In the long run your wasting money on that crap as it is rare they add a game you actually like. Stop being a cheap gamer and just buy the game. It is only $30 on PSN.