Three prostitutes.

There were three prostitutes living together, a mother, daughter and grandmother. One night the daughter came home looking very down. "How did you get on tonight Dear?" asked her mother.

"Not too good," replied the daughter. "I only got $20 for a blow job."

"Wow!" said the mother, "In my day we gave a blow job for 50 cents!"

"Good God!" said the Grandmother. "In my day we were just glad to get something warm in our stomachs!"