The discount is good through June 30, 2018. To get the deal, users need to contact a Microsoft account rep or Microsoft partner, according to the company's website. The deal applies to those with Enterprise Agreement (Enterprise Enrollment, Server & Cloud Enrollment), and/or Enterprise Agreement Subscription Enrollment.
"For a limited time, SUSE is offering customers a self-service promotional code to drive cost savings for SQL Server on SUSE Linux providing a 100% discount on the software cost of SUSE Linux Enterprise Server 12SP3 including free patches and maintenance for 1 year - qualified customers are also eligible for up to 100% discount on 24×7 or 12×5 phone support by working with a SUSE sales rep."
Microsoft used its "Drawbridge" technology, developed by Microsoft Research, to bring SQL Server to Linux. Drawbridge is an adaptation of the Library OS concept. It's a form of virtualization specifically for application sandboxing. Drawbridge played a role in getting the Bash shell to run on Windows 10, too.