SQL Server Management Studio is Free

SQL Server Management Studio aka SSMS is available to download and use for free from Microsoft. You do not require a SQL Server license.

The latest version of SSMS, and future versions, are available from here:

https://msdn.microsoft.com/library/mt238290.aspx

This makes this easier for developers and DBAs that want to work with SQL Server, without having to acquire and install a full, licensed SQL Server ISO.