Usually, I also look at feedback rating. Someone who has lots of (positive) feedback and has been a member here for a year or more usually knows whether they want an item and is just trying to haggle price. New members can be "tire kickers" or just trying to get info about your item for sale. It should take no more than 2 or 3 emails to get a commitment for payment. Furthermore, a contract requires an offer and an acceptance. There WAS NEVER an offer and acceptance with buyer #1, just an "interest". Hey, I'm "interested" in a Ferrari, but that doesn't mean that I intend to purchase one! Further, you had added a time specific option for acceptance which was ignored by buyer #1. As I understand, he never accepted your offer (asking price) or presented a counter-offer (what he was willing to pay). You were VERY ethical by informing him that you had another potential buyer, and giving him a deadline to complete the contract. Hey, "You snooze, you lose!" It's happened to me, as both a buyer and a seller.