Once upon a time in a place overrun with monkeys,a man appeared and announced to the villagers that he would buy monkeys for $10 each. The villagers,seeing that there were many monkeys around, went out to the forest, and started catching them.
The man then announced that he would now pay $20 for each one. This renewed the efforts of the villagers and they started catching monkeys again. But soon the supply diminished even further and they were ever harder to catch, so people started going back to their farms and forgot about monkey catching.
The man now announced that he would buy monkeys for $50! However, since he had to go to the city on some business, his assistant would now buy on his behalf.
While the man was away the assistant told the villagers. 'Look at all these monkeys in the big cage that the man
has bought. I will sell them to you at $35 each and when the man returns from the city, you can sell them to him
for $50 each.'