Loadout is a newly released F2P third person shooter, with a cartoony style, lots of customization, and what seems to be a halfway decent payment model. Some have compared it to a TF2 look, but it's a bit more irreverent and gory. It looks to have a ton of weapons customizations (like maybe Blacklight), as well as a bunch of goofy character customizations. It's been in closed beta for a long time, but has just been released to everybody, and it's on Steam.
The money economy seems to be mostly about cosmetic upgrades and earnings boosts. Most of the gun upgrades seem to be earned with the in game currency alone.
Haven't played much yet, but it seems like a fairly tight, silly, casual arena shooter. Seems to be making the rounds in the press and on Youtube. Polygon covered it in their new video show yesterday.
EDIT: Put a player list in the master GWJ games/platform user name spreadsheet. Here. Scroll right on the PC tab. Friend up.