A guy and a girl go on a date and are parked on a back road some distance from town.
Things are getting hot and heavy when she stops him.
"I really should have mentioned this earlier, but I'm actually a hooker and I charge £50 for sex," she says.
He stares at her for a couple of seconds, shrugs, gives her the money and goes for it.
Later, he's smoking a cigarette and looking out the window.
"Why aren't we going anywhere?" she asks.
"Well, I should have mentioned this before, but I'm actually a taxi driver, and the fare back to town is £75."