A little old lady sold pretzels on a street corner for 25 cents each.
Every day a young man would leave his office building at lunch time and as he passed the pretzel stand, he would leave her a quarter, but never take a pretzel.
This went on for more than 3 years. The two of them never spoke. One day, as the young man passed the old lady's stand and left his quarter as usual, the pretzel lady spoke to him.
Without blinking an eye she said:
"They're 35 cents now."