how much does an actor/actress get paid to do a guest role on a show?

Not necessarily a famous actor or actress but not simply an "extra" either. For example, if for a new episode of CSI or something they cast a young actress (who has had several other supporting roles under her belt) to play a cancer patient or something, and she gets perhaps a total of 18 minutes screen time, how much would she get paid? What if she only had 5 minutes of screen time? What would she get paid then? What if she was only an extra who got one line?