Pardon me, but I'm incredibly lazy so I didn't do a search before posting this but I wanted to pass the name of this game along for anyone who cares.
The game is called Combat Arms and it can be acquired via this website:
http://combatarms.nexon.net/
As far as balance is concerned everything is free, you don't have to pay "real" money to get new weapons or gear (Just cosmetic things, if that floats your boat).
It's a pretty typical OpenGL-Feeling shooter, it kind of reminds me of CS: Source which I never really liked. As a caveat to that I really do find the actual gameplay to be above the normal in regards to my intrinsic enjoyment.
I'm incredibly poor these days both in a temporal sense and in a fiscal sense, so I'm all for free simple games that cost small amounts of the twain to enjoy :)