Re: bottom paint?
IMHO, a bottom painted boat is not something I'd want to purchase... given these circumstances... First off, I'm talking about small pleasure craft and/or fishing boats, not the bigger cruisers.
Realize that a bottom painted boat will (practically) need to re-painted, annually, forever.
If a boat is to be kept on a lift - salt or fresh - bottom paint is irrelevant.
If a boat is to be kept on a trailer - salt or fresh - bottom paint is irrelevant.
If a boat is to be moored in salt, then it is worth while.
When I got my Sea Ray, it was painted and I was going to keep it moored in salt for 6 months and then in fresh for 6 months. Then the barnacles ate the in-poor-shape bottom paint. Then I got a lift for the salt location, and it sits moored in the fresh. That was my first major lesson in salt water! I still need to refresh the bottom paint annually, just to keep it looking OK.
Granted, the fresh water gets a little slimey from algae, but a little oxalic acid melts it off at the end of the season. And algae doesn't "eat" the hull like barnacles.
I would not pay big bux for a painted hull. I would pay less.