It's a summer holiday weekend and a man walks into a butcher shop which has a sign in the window saying "Ground Sirloin: 29 cents per pound" The man says, "I'm having a cookout this weekend. I'd like 5 pounds of your ground sirloin, please."
The butcher shakes his head and says, "Sorry. I'm all out."
The man, disappointed goes down the street to another butcher shop and asks, "How much is your ground sirloin?"
The proprietor replies, "It's $3.29 per pound."
"Three twenty nine!?!" exclaimed the customer. "Just up the street he sells it for 29 cents!"
The butcher smiles calmly at the gentleman and asks, "Does he have any?"
"No. He's out of it right now."
"Well," says the butcher. "When I don't have any, I can sell it for 19 cents per pound!"