Big cost may be marina
Depending on where you are, marina space can be cheap or very expensive. S. Florida, 40 ft slip 2 years ago where 6 to 800 or more per month.27 foot slip would be much less. Other areas are not so expensive.Where I am, slip space for a 37 foot boat can run from 200 or so for storage, up to 700 for live-aboard in a fancy marina.Call some marinas in the area where you would keep the boat and see.The other costs will depend on how much you use it.My big expense, after marina space - I live-aboard - is upgrades. Not upkeep and repairs, (I have plenty of those) but upgrades. My autopilot needs replacing. I could spend 700 to replace what I have, but it is undersized, so I will spend 3 times that much (nearly) to upgrade to what I really need.