A Minute Job

A dentist is trying to pull out the patient's tooth. While doing his job, his patient asks:

Patient: How long will you pull my tooth out?
Dentist: Don't worry, it will take a minute for me
              to pull your tooth out.
Patient: And how much will it cost me?
Dentist: Just $100.
Patient: For a minute job?!
Dentist: If you prefer, I can pull it out for one hour.