FusionFall offers a free-to-play area for users to get a taste of the action before deciding if the monthly subscription (which starts at $5.95) is worth it or not. In our admittedly brief time with the game's beta last year, we found the combination of Phantasy Star Online style combat and platform game elements surprisingly appealing. (Especially considering that the game is primarily aimed at kids and those in their early teens, i.e. not us.)
For a deeper glimpse into FusionFall, our friendly neighborhood MMO gurus at Massively have put together a really swell guided tour of the game, which you can toon into by clicking here.