Global Agenda has a free trial. Try it.
Whenever I see Global Agenda on Steam I can't help but think that it's about a planet that harbours evil intentions. Sadly, this is not the case. It's a third person, class based team action game with MMO overtones. Also, up to level 12, it's now completely free to play. Hooray!
You can sign up here. As well as the level cap, there are limits on the kinds of missions you can run, you won't be able to discover the best items or join Agencies (Global Agenda's equivalent of Guilds), but the rest of Global Agenda is yours to explore, and by explore, I mean "shoot in the face".
Most of the game revolves around 10 v 10 multiplayer skirmishes, with kills and successfully completed objectives netting you experience points that can be used to level up and boost your class skills. If you like the game enough a one off payment will get you access to the game proper, removing the level cap and giving you access to the full suite of PvE missions. The level cap will disappear, too, of course. If you want more you can pay a monthly subscription fee to access the 'Conquest' meta game. This is a larger PvP territory war that sees Agencies, in a traditional PC gaming fashion, waging war for control of sexy hexes that can earn the controlling Agency vehicles, money and fame.
Did I mention the jetpacks? It has jetpacks! And a hilarious melee system where you can hold up a shield to reflect all melee damage back at your opponent, thus causing him to punch himself to death.
EDIT: We made a boo-boo. Global Agenda does not require a subscription for the Campaign mode. We apologise for any confusion.