I feel your pain. Startups aren't friendly to the cushy .NET environment. I've seen plenty of other middlewares such as Java, Scala, Python, Ruby, and Node, but no .NET.
I wouldn't have any trouble spinning up a product on that stack if I knew I could deploy it without spending a lot on just the software stack (especially if I was bootstrapped)
Their partner program action packs are relatively cheaper than buying the individual products ($429 Design and Dev action pack includes pretty much everything) or an MSDN subscription.
Their BizSpark program is aimed at keeping costs low during development and Azure has simplified deployment (1 shared instance + Sql Database + 50GB bandwidth for $25/mo).
I've found Node to be a good supplement for some middleware (but it still has bland RDBMS support especially with SQL Server).