Just a quick question: is it worth it to spend 500$ in MCSE Windows Server 2012 certification today?
MCSA Windows Server 2012 still relevant...?
This is dependent on the job market you want to enter. If the company that you're working for or looking to work for is saying this is a requirement or the equivalent is required along with another certification then yes.
If your area has moved on to another product then may not so much so. But as with everything, it's about market when you talk about relevancy. The skills you would have learned in a previous version such as Server 2003 or 2008 will help in Server 2012 and beyond. So in that sense, the knowledge gained may serve you well later too!
I would agree with Ronnie. Windows Server 2016 is still in beta, and probably will be until late 2016. Most organizations will not move to Windows Server 2016 immediately, nor will they upgrade the entire enterprise at once. So Windows Server 2012 certifications remain very relevant.
Plus, most of the skills and knowledge you learn obtaining your MCSA 2012, will still be applicable for the MCSA 2016. DNS is still DNS, DHCP is still DHCP, etc. There will be some new concepts you will have to learn, new features in Windows Server 2016, but the majority of the information will carry over. So that much less studying when it is time to get your MCSA 2016.