I am developing a mapping application using ESRI Silverlight API (it's SL map control). I am not using ArcGIS Server whatsoever. Once this map application goes commercial (plan for clients to use it - not that many by the way), will I have to pay any pay-per-hit usage or any other related costs? I know that both the Google Maps API and the Silverlight Bing Maps API cost or correct me if I'm wrong.
Any and all advice will be greatly appreciated.