Good bye, Mother!

A young man was walking through a supermarket to pick up a few things when he noticed an old lady following him around, but he ignored her and continued on.Finally he went to the checkout line, but she got in front of him.She said: "Pardon me, I'm sorry if my staring at you has made you feel uncomfortable. It's just that you look just like my son, who just died recently."The young man replied: "I'm very sorry, is there anything I can do for you?""Yes, as I'm leaving, can you say 'Good bye, Mother!'? It would make me feel so much better."The young man answered: "Sure!"As the old woman was leaving, he called out: "Goodbye, 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!"The clerk answered: "Your mother said that you would pay for her!"