You may get all kinds of interesting answers. It really depends on the job. I can tell you that I would charge more for having to mortise the hinges and what not than I would to just hand a new pre-hung door. Less liability, less trouble and less headache.
One thing to consider is how clean and neat is the job expected to be. Is the house a construction site that you can come and go as you please? etc...etc....
To hang a pre-hung door, including removal of the old door and trim. I charge $100. I will fur the jam out for trim installation and install the door handle but that's it. No trim or anything else. If I were doing the same thing in a house that was under massive construction my price could drop down to $75. This of course is with multiple doors. One door wouldn't be worth the time to even drive over.