A few months ago I did a series of photoshoots of authors at a literary convention, as a (stringer) press photographer for a minor online publication. Yesterday the agent of one of the subjects I shot got in touch with me, wanting permission to use images from one of the shoots for marketing/promotion/&c.
This use of my work is completely new to me (I've done some wedding photography, and sold some prints, but nothing else). It's a quite successful author and a major (European) publisher, so I'm loath to just not charge, but I don't have any point of comparison at all to base a rate on.
What is a range of rates people have used in the past for this sort of thing?