Well it can depend on how you move your images, who buys them, how large a print, Magazine, ad, or web publish etc.

An example of the last event I went to at Goldendale is that I have sold two CDs containing 25 images to two seperate purchasers for mixed useage and a third for private ownership. The deal hasn't been finalized but I stand to make well more than I spent to get to the event and also covers all incidentals with plenty left over to throw a raging party at the bar.