A kid sets up a lemonade stand in front of his house, with a sign that says, “All you can drink for a dime.”
Before too long, a man happens by, sees the sign, and thinks it’s a good deal. He gives the kid a dime and the kid hands him a cup.
The man tosses it back and says, “Hey, that was pretty good. I’ll have another.”
The kid says, “That’ll be another dime.”
“Now wait a minute,” says the man, “your sign says ‘all I can drink for a dime.’”
“But you just had a cup, didn’t you?” asked the kid.
“Yeah.”
“Well, that’s all you can drink for a dime.”