A young man was walking through a supermarket to pick up a few things when
he noticed an old lady following him around. Thinking nothing of it, he
ignored her and continued on. Finally he went to the checkout line, but she
got in front of him.

"Pardon me," she said, "I'm sorry if my staring at you has made you feel
uncomfortable. It's just that you look just like my son, who I haven't seen
in a long time."

"That's a shame," replied the young man, "is there anything I can do for
you?"

"Yes," she said, "as I'm leaving, can you say 'Good bye, Mother!' It would
make me feel so much better."

"Sure," answered the young man. As the old woman was leaving, he called out,
"Good bye, Mother!" As he stepped up to the checkout counter, he saw that
his total was $127.50. "How can that be?" he asked, "I only purchased a few
things!"

"Your mother said that you would pay for her," said the clerk.