But it's a restricted type of subscription. For example you can't reserve instances.
Interesting. So the premise of the article is wrong, where he says he only gets $300 a year. Apparently he even works in Azure. Would have thought he would get more given the role.
Yes, it's the standard Visual Studio Enterprise credit that you get with the license - 150/month
Which means that you need a Visual Studio Enterprise license that costs $500 a month, unless you can get it though partnership programs. I take it OP doesn't have an Enterprise license.
Every Microsoft employee is given a license as part of working there, at least if you're in the eng orgs.