My mom and I love to garage sale. We are known for making deals and pride ourselves when we do. I found these Dr. Brown's bottles and the man was telling me how expensive they are and said "how about a dollar"? I then replied and said, will you take $0.50? He paused, was struggling and then said hesitatingly, "yes". He then asked if we were from the community. We informed him that we were from around the area and then began to tell us that this community was to benefit a little girl that was born with half a heart and that all the proceeds were going to help this girl. Apparently, the guy I ripped off is the father of this girl, and he politely told us how well she was doing.
... I felt stupid, told him good luck and what a good dad he was, and embarrassingly left.
To conclude, just don't be stingy and pay the whole buck.