Yeah it is called being a bad seller if you asked for an amount, then got offered that amount, but then did more research on how much more you want to raise it again.
Your bike is worth whatever someone is willing to pay for it in it's "current" condition in your market. Put it up on ebay or bringatrailer.com if you want to get top dollar for what it could be. But even then those might not bring the kind of money you now seem to expect out of what was just recently a $250 bike.
Bob, you are wrong. You were not a part of the original discussion and no one had been telling anyone to rip off a seller. As a buyer I would hope you attempt to haggle on the price. A seller can counter but cant counter with a now higher price than the previous asking price. Ya get me?