Eve Online
Basics:
EVE Online is a persistent world multiplayer online game set in space. Players pilot space craft that vary in size, style and purpose. Become a cold-hearted mercenary, a savvy merchant, a cut-throat space pirate or any number of other things!
Cost:
You can play Eve Online for FREE with the 14 day trial membership.
After the two week trial period (if you like the game) EVE Online only costs $15 a month (slightly higher in Europe).
