An old man walks up to the counter of a pawn shop holding an old, weathered guitar:

“I’d like your expert opinion on this guitar, how much do you think it’s worth?” Asks the old man.

The pawnbroker looks it up and down.

“Well, I can tell right now that there’s a little warping in the neck, the lacquer is faded and there are scratches and dents all over it. It’s an old, well-played guitar but I don’t think it’s worth any more than twenty bucks.”

The old man reaches his hand out and says.

“Okay, if that’s what you think it’s worth, you have a deal!”

“Great!” Replies the pawnbroker, shaking his hand.

“Here’s twenty bucks.” Says the old man.

“I’ll buy it right now!”

The broker stops and suddenly looks confused.

“Wait, buy?” He asks.

“Yes!” Smiles the old man as he flips the guitar over.

“This one has a sticker price of $150, but now that I have your honest opinion I think twenty bucks is a great deal.”