I read on Princes Cruises it cost over a grant to marry on the ship, is there a way to marry on the ship4less?

I read in Princes Cruises costs more than a subsidy to get married on the boat, there is a way to marry in the ship4less? I do not want flowers, do not want champagne, I walk with my boyfriend and get married and leave. That’s it, you really have to cost a great?