4 days of back and forth on a Trek steel bike for $130? If I was the seller, I would have moved on to another buyer myself. When you are ready to buy a bike, jump in the car, cash in wallet, and negotiate in person.

Personally, I just delete emails from people that want to negotiate that way.

And Craigs List is the land of no shows. The first one with the cash wins.

As far as the sold out for underneath you problem (which has happened to me several times), my basic rule is call when you leave the house, and I will hold it until you arrive. I have used this with good success on buying bikes and selling bikes.