SQL Server Developer Edition 2012 or 2014 - Download
Developer Edition is free 


As of March 31, 2016 Microsoft SQL Server Developer Edition is now free for SQL Server 2014 and up for Visual Studio Dev essential members (which is free as well).

For all editions, see How to buy SQL Server.

If you want to explore SQL Server, you can download SQL Server Evaluation Edition for 180 days, and then purchase it.


Microsoft® SQL Server® 2014 &amp; 2016 Evaluation
Microsoft® SQL Server® 2012 Evaluation