I think Michael has it right. I also think you have to treat it like a real auction. From the description and pictures, decide what you think it is worth and never go beyond that price. You can make an offer and negotiate up to that price or simply say that you have evaluated his description and you think the right price is such and such and see if he goes for it. It is often wise to give a contact number if he changes his mind in the future. Sometimes, once there is an offer on the table, the guy mentally spends the money on some other thing and comes back to you because he now wants the money to buy that. Best of luck.
