The Mrs and I started playing Star Trek Online last night. It's quite a lot for being completely free. The only things that seem to cost make the game easier (having more slots for bridge officers) or are purely aesthetic (make your ship look like Kirk's Enterprise). They even sell one of the currencies.

I got what I wanted out of it, the starting ship can be a Miranda-class (like the Reliant from Wrath of Khan), which mine is named "U.S.S. Indianapolis", captained by "Lt. O'Five". My wife has a custom ship (you can use pieces from three similar classes to make your own style), the "U.S.S. Tyberius", captained by "Lt. Mrs. Paris".

Fun stuff.