The TERA Website has news that En Masse Entertainment's MMORPG is going free-to-play next month (thanks Massively). This FAQ has all the details, and here's a bit:

TERA will be free.

No level, time, or content restrictions.

Our philosophy is to add to what we already offer instead of restricting existing content. We've added an in-game shop where players can choose to buy costumes, mounts, and consumables, but the core of the game will be 100% free.