2) (gaming) The ability to do something without fear of retribution.
3) (gaming) The ability of one character/weapon/strategy to destroy the opposition.
4) An easy win.
2a) You can't jump in against him for free!
2b) Aww man, once you corner him, you can chip him to death for free!
3) You gotta just zone his ass out- you'll win for free if you do that!
4) Damn! Vega's not for free no more in SSF4!