Charging by the situation

Like a dud, I left the lights in my car on. By evening, the battery had drained out. So, I had to hunt for a battery shop and finally found one. He came along with a spare battery and jump started my car. It only took him a minute and he charged me Rs.50. I had to pay another Rs.50 for his tranportation. I thought that was easy money. All he had to do was bring his battery and take it back. How folks charge when they know you are stuck in a quandary!