If you want to see something more than a flat mud bottom (like wrecks), it is a 1.5 hour drive to the Charter Boats, and a double tank on Lake Erie is going to run you $110-$160, rentals, food, incidentals. Easy $200 day. Dive 5x and it is $1k...
I can do shore based drift dives in the Niagara River for "free" weekly. I have all my own gear, including a compressor... through the local shop, gear rental package for their get together is $40... Sure, it could be done, but it can get somewhat boring to drift the same spot every week.... Different spot? You need your own boat... I do that too... lets not factor in the cost of a boat...
I travel to the Thousand Islands/St. Lawrence River. It is 4 hours to get there, and fuel, accomodations, charters, food, air.. it is going to add up.
Tobermory is further, and costs even more...
Yeas, it is $1,000 a year to do nothing fancy....