Is ESRI Silverlight Mapping API Free or exactly how much (also what about Silverlight Bing Maps)?

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开发者_如何学JAVA Maps API cost or correct me if I'm wrong.

Any and all advice will be greatly appreciated.

It's basically only free without an ArcGIS Server license for non-commercial use. Here is a link to the detail: http://www.esri.com/software/arcgis/web-mapping/pricing.html

Basically the same goes with Bing maps, free for non-commercial use, and per hits cost with commercial use. Google maps has a lot more red tape for commercial use. Bing seems to be more commercial and business friendly with their terms of use where Google seems more consumer focused.

I hope that helps.