The map surfaces provided by the C1Maps control (VirtualEarthRoadSurface, VirtualEarthAerialSurface, VirtualEarthHybridSurface) use the Bing Maps API. Usage of these online tile sources is not free for commercial use. You can learn more about using Bing Maps from the Microsoft documentation below.

http://msdn.microsoft.com/en-us/library/dd877180.aspx

Using a Bing Maps Key in your code is the recommended method of authenticating your Bing Maps application using C1Maps. Bing Maps Keys do not expire, and a service request is not required to obtain a key.  Therefore, it is very easy to authenticate your application using a Bing Maps Key and the C1Maps control.