Digital BW, The Print

Greetings --

I am just entering the world of selling my photographs and I would 
appreciate any input to the following questions:

* What is considered a reasonable print run for a photograph?
  I arbitrarily picked 250.

* Is the negative destroyed after the run is complete?
  I would guess so.

* Do different print sizes count in the total number?
  I would guess so.

* Is there an Internet site or book that explains the "rules"?

Thanks. I appreciate your input.

David Douglas
douglas@...