Economics Lesson from Tom Sawyer
"Say -- what's that?"
"Nothing but a tick."
"Where'd you get him?"
"Out in the woods."
"What'll you take for him?"
"I don't know. I don't want to sell him."
"All right. It's a mighty small tick, anyway."
"Oh, anybody can run a tick down that don't belong to them. I'm satisfied with it. It's a good enough tick for me."
"Sho, there's ticks a plenty. I could have a thousand of 'em if I wanted to."
"Well, why don't you? Becuz you know mighty well you can't. This is a pretty early tick, I reckon. It's the first one I've seen this year."
"Say, Huck -- I'll give you my tooth for him."
"Less see it."
Tom got out a bit of paper and carefully unrolled it. Huckleberry viewed it wistfully. The temptation was very strong. At last he said:
"Is it genuwyne?"
Tom lifted his lip and showed the vacancy.
"Well, all right," said Huckleberry, "it's a trade."
Tom enclosed the tick in the percussion-cap box that had lately been the pinchbug's prison, and the boys separated, each feeling wealthier than before.
That last line captures the essence of a free market system. The only transactions that should occur are ones in which each party values what they're receiving more than what they gave in return.
(Thanks to Susan Hogarth for this illumination.)