When I was delivering pizza after high school/before college, I had a woman try to do that "Oh no, I just realized I don't have any money. Is there any other way I could pay for this?" I had a partner at the time so I was just like, "Nah, it's on the house."
Another time I was delivering to a hotel and stopped to ask a woman where a room was. She pointed me in the right direction, then said she was trying to make money to keep her and her kid in a room for the night and would suck my cock for $100. I gave her a $20 and wished her luck.