It's awesome that you lived on a boat and only paid $300/month on marina fees. How much did the boat cost?
If you're looking to save as much as possible, you can get boats for $1,000-$7,000 that a single person can live aboard fine (or two people towards the higher end of that scale)... and by going out of the urban area to more remote locations you can get cheaper marina slips.
(That means if you have a decent interest rate and reasonable risk tolerance, you can invest the cash elsewhere and make more money than you would save by buying the boat outright.)