If you sign up for Microsoft VS Developer Essentials you can now download and use SQL server Developer Edition for free.
This version has all the features of Enterprise Edition used by many large corporations and can be used to build SQL Server clusters etc.
I also noticed that the new R Server Developer Edition is free - and is available in versions for Windows/SuSE and Red-Hat.
$25 a month of Azure credit is also now included.
Microsoft are definitively keen to suck in as many new users as possible - take advantage :-)