Oddly enough, I just ended up with a Mars Trek last Saturday.
I have some pinball machines just outside the elevator lobby where I work. Someone who works above me heard the guys playing when the elevator door opened. He came in asking about the machines. I was called out to talk to him.
He is selling his house and wanted the machine sold before he moved. He didn't know how much it was worth so I did some research and sent him an average price we can start at - $550. The value of his machine would go up or down from there.
I went to look at the machine. It was ok. Nothing major wrong with it, just filthy, a little cabinet damage, etc. It should clean up well. I offered $600 - he wanted $900. I might have paid $900 if it were beautiful and didn't need work, but it wasn't and it did.
We shook hands, I thanked him for showing it to me, and I left without the machine.
2 hours later I get a call. His wife came home and tore him apart because she wanted that machine gone. I could hear her in the background. She was not happy.
I went back and bought it for $600.