I am IMO one of the Best F2P MMO's around the game is exactly what I wanted alot of FPS's to be like no Grenade spamming on respawn, ammo is realistic and
the world is AWESOME looking too. I love been a gunner in a galaxy too
It's free to play, with micro-transactions ingame. Some stuff can be bought with ingame credits you earn by playing though. I think the weapon system is reasonably balanced, but i'm unsure.
I saw a review about this game and the guy said that there are no weapons you can't purchase for free, but buying credits will allow you to get them faster.