I am looking for a C# programming compiler on macOS that is a good value.
Could you give me any advice?
It supports development of the following:
For iOS development, macOS Sierra 10.12 and Xcode 8.3 are required.
The Mono project maintains a cross-platform C#/.net environment which works well on macOS.
I recommend Visual Studio Code (https://code.visualstudio.com/). It's an official Microsoft product, so it should run C# quite well. When you have it installed, click on the last large button in the sidebar to get extensions, and search for C#. (There's also a Windows version.)