I had a similar situation earlier this month. I posted my mountain bike for sale on craigslist. I posted it for a very good deal not really realizing what it was worth. I recieved an E-mail and a call from a guy whom wanted the bike but wanted to negotiate. Another man emailed me a minute after I got the first email and I told the guy I was on the phone with that the price was firm. He said he wanted it. I emailed the other guy back and told him that the other buyer was first and if it fell through he was next. He emailed me back offering more money. I realized I had listed the bike at way to low a price and was kicking myself, but as I told my sons that day, he was first in line and thats that, although I could have used the extra $100 (yea that much and that hard to turn down) fair was fair and he was first. We had made a deal and as long as the first guy followed through (which he did) he would get the bike. It was my mistake and a mans word is his bond.