A Profitable Harmonica

Thanks for the harmonica you gave me for Christmas," Little Johnny said
to his Grandfather. "It's the best Christmas present I ever got."

"That's great," said his Grandfather, "do you know how to play it?"

"Oh, I don't play it," Little Johnny said. "My mom gives me a dollar a
day not to play it during the day and my dad gives me five dollars a
week not to play it at night."