Three friends decided to visit a prostitute. It was a slow night, So she gave the guys a deal. "You can pay by the inch."
When the first man comes back out his friends ask, "How much did she charge you?"
"$75 dollars," said the first.
The second guy goes in and returns with a fee of $85. The first two were proud of their prowess.
The third man goes in and returns, "How much did she charge you?" ask the first two.
"$20 dollars" replies the third.
The first two start laughing hysterically.
"Hey guys," replied the third, "I'm not so stupid, I paid on the way out instead of on the way in!"