VS 2010 is free if you sign up for their webspark program http://microsoft.com/web/websitespark/ -- so is MS Windows Server 2008, SQL Server, etc. Look, I'm no MS proponent. I'm an independent developer and I use all platforms, all tools, all languages. If you fellas watch the news, this URL is kinda like the Fox News of Apple fan-boi-ism. Fair & Balanced...it is not...tiresome...bah, let the downvotes begin.
You can download application and device driver SDKs which come with command line C++ compilers at no charge. Pretty much the same compilers MS uses to build the OS itself and its own products.
There's also a no charge "express edition" of the IDE, but it was heavily crippled last time I checked.