Frankly, I think if anything C#/.NET is cheaper.
I guess you're too young to have witnessed Microsofts marketing strategy in effect. AND well documented...
I hope you're not thinking of MSDN. The only good thing about MSDN is that it's indexed by Google. Plus 99 out of 100 times, you're going to find better documentation, articles and examples on http://www.csharpcorner.com/ or http://www.codeproject.com/ And of course, mono is free and available for a bunch of platforms
It's also no where near as complete as .Net.