Re: Where to get a good used trailer?
Some boat dealers will have taken an old trailer in from a trade.
Ask around the stack storage (bulletin board?) as there may be people who are stacking and don't want one any more. Or with the right person, buy one together (Hmmmm new business idea: boat trailer rental for the occasional user...)
Boat junk yards/used boat dealers
Best idea for one that size is the "almost free boat." Around here, the 25' cabin boats are always cheap--they don't last, or a lot of the owners aren't serious boaters I guess. Even if you get a wreck of a trailer, replacing the springs/axles is simple and not too expensive; focus on the frame (not painted, as said before, and see if you can see inside the tubes). You are going to need brakes, so whatever you buy cheap will need brake work anyway.
The more I think about it, sharing one makes good sense. I wish someone would share mine; I hate having it just sit there, paying storage, insurance, taxes, etc. for use about 4x a year.