It's 12.95USD per month to play.

I can't really tell you if it's worth buying, it depends if you like MMO's or not. This is a very time consuming game, and as you get higher in level and progress, you'll be spending a lot of hours per sessions just to get some things done.

That said, it is a fairly good game, it's kept me occupied for a couple of years and it's relatively cheap to play. I say just look around at fan sites and get all the information you can before you commit to buying it (you can't return it).