Can someone tell me the way you pay for this game?
Start HereChoose either a 14 day trial (Which you can convert into a paying account during or after the trial) or choose to buy it on the spot.
One month costs $15 USD, slightly less per month if you buy them in multiple month packages.
You can choose to have your subscription automatically payed for whenever your time starts to run out; or not in which case it will warn you in-game a few days prior to your account being terminated.
TL;DR it's a subscription