Is SQL Server Data Tools a paid product of Microsoft or a Free Product? I don't find an evidence in Microsoft Pages regarding SQL Server Data Tools Licensing and Price details. 

https://docs.microsoft.com/en-us/sql/ssdt/download-sql-server-data-tools-ssdt?view=sql-server-2017

Here all the instructions to download and install SQL Server Data Tools and no term mentioning it is Licensed. 

As I understand searching for such details are to up to our responsibility but I didn't get a clue for it. So my question is SQL Server Data Tools is Free or Not? If Free then Shall we simply download and install as instructed in the below link? If Paid, where is the pricing details?

https://docs.microsoft.com/en-us/sql/ssdt/download-sql-server-data-tools-ssdt?view=sql-server-2017
It is free and a part of Visual Studio Community Edition.