Thanks, I have my operators license so I'm good there. I'm looking at smaller bowriders, hoping the gas won't kill me.
I'm assuming that you going to be trailering it in and out of the water at public-use boat ramps each time you use it?
If so, you'll be able to save a decent amount on fuel by avoiding the marina fuel pumps and gassing up at the local Pioneer or Cango instead when you head out. Just pick up one or two extra fuel containers for the boat, preferably boat-specific ones with the quick disconnect for the fuel hook-up.
It's good insurance to have extra fuel on board in any case, especially if you're running anywhere far offshore like deep into Lake Ontario or Georgian Bay. That way you're not at the mercy of hoping for a passing boat, especially at night when you're less visible and other boat traffic gets much scarcer.
Some people I know just use the cheap general purpose 5-gallon containers like you'd keep at home for the lawn mower or garden tractor, but they can be tippy in a boat. Refueling with one of them while bouncing on the waves is a great way to leave you and the boat smelling of fuel, and the only quick way to get rid of that smell is to burn it off, which actually did happen to a friend of mine.
Your actual fuel usage can vary hugely. My bowrider was an 18 foot heavy fibreglass job with a deep tri-hull, and it was pushed by an older 110 HP Mercury inline-6. Getting it up on plane required plenty of throttle but once it was up on plane it didn't need much power to stay up unless the water was overly-choppy.
An aluminum-hulled boat with a skiff-type bottom will be a lot lighter and can get by with a much smaller motor. The newer motors with a decent prop are also a lot more efficient than the older stuff. Pulling a water skier behind will hit the fuel hard. Leisurely skiffing on smooth water or river won't.
Mine was used for primarily for water skiing and frequent fast lake crossings to the New York side of Lake Ontario, and that meant frequently choppy water if not outright heavy waves combined with some heft distances. That sucked fuel back hard, especially given the heft of the boat and the motor on it.