Lookie!
Introducing Visual Studio’s Emulator for Android
Current limitations
•If your app makes direct or indirect use of OpenGL 2 or higher, that will not render on our emulator yet. This support is coming soon, and looking at an early internal-only build that I have it does make the image feel even snappier!
If there’s a plan for monogame to support .net core someday… that would be awesome! That’s like saving 300$/year per platform.
Too good to be true for now 
Free C# on android ???
No. C# for Android is still a commercial product from Xamarin. It will have more comprehensive integration into Visual Studio 2015.
Then my question is.Will monogame run on android in 2015 whitout paying anything?
It might be possible with the increase in maximum app size in Xamarin Starter Edition announced on the Xamarin blog this week. More will be known in the coming weeks when it is released.
As for completely free Android development in C# with no restrictions, I doubt it. Microsoft have not bought Xamarin. The Visual Studio 2015 Preview supports Android with Cordova and C++ natively, and with Xamarin.Android installed it supports C#. Xamarin.Android is still a separate product.
AAhh make sense. Now if only iOS works on VS2015, that would be awesome.
That double the size limit of app is interesting.