Re: "You make your money buying the boat, not selling it."
Spot on in my opinion. When you buy you need to screw that price down to the lowest possible no matter how much that may offend the sensibilities of the broker or the seller. As was essentially mentioned earlier in the thread every dollar you knock off the buying price is money to be invested and interest to be earned. Alternatively it gives a boost to the cruising kitty.
When we were negotiating price of our current boat two things were said ...
1. You are trying to buy a boat not make new friends.
2. At the end of the day if you think you paid too much and the seller thinks you paid too little then the price was probably spot on.
“Give a man a fire and he's warm for a day, but set fire to him and he's warm for the rest of his life.” Terry Pratchett