It always amuses me how some people just expect to get some crazy-*** deal just because they want one. It's even better when it's really obvious that they are bluffing and are really really bad at bluffing.
We did a garage sale a few years ago and I was selling this really nice tricycle for toddlers that we used maybe once. One guy came up and offered me 1/4 of what I was asking and I told him no. Then he tried adding $5 to it and I said no. He made a big production and loudly said "Well, I'm just going to leave then."
10 minutes later, he walks by (presumably checking to see if it sold)
30 minutes later he came back, picked up a few books, and said he'd add another $5 to his offer if I included these books. I took the books from him and told him to get off my property.
Two other people there actually started clapping. Apparently he'd been pulling the same crap at other garage sales, annoying everyone around him.
That was the last garage sale that I will likely ever have. When you sell a $10 item for $.50 and someone has the nerve to say "I'll give you a quarter" I'm much more inclined to break the item and throw it away in front of them than give some d-bag the satisfaction of saving a quarter.