Hi Chuck, good luck with the commision, please note though - that the artist typically retains copyright on the work but licenses (and that can be exclusively) it out to others. The price will normally be determined by how the artwork will be used. So if its for a single chart the price is low, if its for continual use, and perhaps in different charts, maps, books etc - the price will be higher, and if the map may not be used by any others the price raises again. However the artist will always retain the right to use the work as a part of his/her own portfolio ... hope that helped a little