Re: where to find used boats?
Lets Fish,
Craigslist, the local papers, and the local marinas (take a look around Lake Hoptacong) have the used boats and you can go see them in person. I would stay away from ebay, unless you can go see the boat.
Also ask friends, post signs at the local food store bulletin board, diner, etc.
The first boat I bought was found by a guy I work with who brought me an add from the local 7-11. Let your friends and co workers know you are looking.
The second boat I bought came from Craigslist. I drove almost 3 hours from north NJ to south NJ to buy a boat I found on Craigslist after searching back a few weeks. Turns out it never sold, and I got it at a little less than the asking price. I talked to the guy on the phone, told him I was making the 3 hour trip, and would he hold it for me regardless of who showed up before me. He did, and lucky for me, no one else beat me to it. I paid cash ($1875, so not a big risk), took the title and documents, and came back a few days later to tow it home.
So it pays to talk, make plans, make your intentions known, be prepared to change hitch ball sizes if needed (2" and 1 7/8" are common).
Good luck.