I read a story on BMX Museum about a guy who found a good deal, called and arranged to go pick it up. When he got there the owner demanded TWICE the asking price. What happened was that on the hour+ trip another member of the Museum called on the item and when they found out someone else was coming to get it (and therefore, they couldn't) they told the owner it was worth much more and not to sell it as cheap as they listed it. What a jerk.
The same thing almost happened to me, but I won't blame another member. I had found an ad and left messages about it on a Wednesday afternoon, that evening I arranged a pick-up the next morning, it was 80 miles away. This was for my 1956 J.C. Higgins tank bike for $40. When I got there the guy said he had lots of people calling about the bike and offering him MORE money to sell it to them instead of me. I'm glad the guy selling it was an honorable man and kept his word to me first.