OK, it is official, Microsoft has gone insane. Starting March 31, 2016, SQL Server Developer Edition is now free. First it was Windows 10 upgrades. Then it was Power BI. And now the developer edition of SQL Server.
Of course, the developer edition has never been expensive, usually just $50. Still, this will make it even easier to move SQL Server closer to wide spread use.
Visual Studio Dev Essentials may nolonger be necessary:
Key Point: you will need to have a free membership in the Visual Studio Dev Essentials program. But, again it is free. Find out more about Visual Studio Dev Essentials.
You can find out more here: SQL Server Blog - Developer Edition is now free.