This bloke rings up his dentist and asks him how much for an extraction. The dentist replies £60. The guy asks how much he would do it for without the freezing injection. The dentist says without the injection it would be excruciating and very traumatic but that said, it would shave £20 off. The guy had him on the move now and was keen to hammer him even lower. Ok, have you any students there who could do it with your supervision asked the bloke. Well yes i have but this is getting highly irregular replied the dentist. Never mind about that said the bloke, how much off then. The dentist replied £20. Great said the bloke, i`d like to book the wife in for friday morning.