Where?
Bottom paint? How many owners? Do you have paperwork to back up maintenance claims? Does the hour meter on the boat and engine ECU agree?
I have to say somewhere around $25,000 without a trailer, but I'm in California so that's just a guess. A new galv trailer set up for a Parker 23 is about $8,000 here in So Cal.
I've seen older boats go for around $20 with an older motor and no trailer. From what I've seen East Coast and Florida boats go for about 15% to 30% less than out here depending on the season.