Microsoft recently posted an MSDN Flash Newsletter message about the availability of Visual Studio Express 2013 which provides for an no-cost, unlimited usage period.
Visual Studio 2013 is useful to develop and test C# scripts which will eventually be used in APL+Win via the APLNext C# Script Engine.
http://www.visualstudio.com/en-us/products/visual-studio-express-vs
For CSE purposes the Visual Studio Express 2013 for Windows Desktop is probably the most useful version.