A Scotsman phones a dentist to enquire about the cost for a tooth extraction.
"£85 for an extraction, Sir," the dentist replied.
"£85!!! Have you not got anythin' cheaper?"
"That's the normal charge," said the dentist.
"Whit aboot if ye didnt use any anesthetic?"
"That's unusual, sir, but I could do it and knock £15 off.
"Whit aboot if ye used one of your dentist trainees and still without an anesthetic?"
"I can't guarantee their professionalism and it'll be painful. But the price could drop to £40".
"How aboot if ye make it a trainin' session, ave yer student do the extraction with the other students watchin' and learnin'?"
It'll be good for the students", mulled the dentist. "and it's going to be very traumatic, but I'll charge you £5."
"Ooh, now yer talkin' laddie! It's a deal," said the Scotsman.
"...Can you confirm an appointment for the wife next Tuesday, then?"