I have a customer that's no longer using his 25, what's it worth? 454 carb Mercury bravo with a manning trailer. Always fresh water.

I would say 16 to 20 depending on hours and condition.

Not knowing all the options NADA has the total value at $14,250 low retail and $16,260 average retail. Boat alone at just over 15k. Easy free web site you can plug in all the options for a more accurate number.
http://www.nadaguides.com/Boats

Thank you.