Carl Klitzke , Jul 30, 2008; 04:49 p.m.
As much as you would like. You could charge $50000 for an 8x10 if you want. Probably the best thing to do is consider the cost of the print (to you), the time/difficulty in getting them printed, and how you price otherwise. Some photogs go cheap up front and then make money selling prints, others do exactly the opposite. As far as printing goes, make sure to use a good lab and get to know the people who work there.