But, as perspective, MS Dev tools cost about $10K per dev + $3K per year per dev after the first. Engineers costs $100K+ per year. +10% productivity covers the tools. If it costs you a month to retool or saves you a little on salary or lets you hire a little easier, you have paid for the tools. So what matters are things where you get x3 productivity or x3 better ability to hire.
Also, I think you are asking the wrong question. The problem you are trying to solve drives the platform decision and language (even DB) are only a small part of the equation. Amazon works just fine with C#/.Net and it is cheap to free at first. To get a fair comparison at scale, you need to include the price of EC2 instances against a dedicated self-hosted database server. Depending on your application, you'll get very different answers.
In your shoes (based on limited info), I would try to get into the BizSpark Cloud program. It is free MS software plus a big credit on Azure for three years. Then count on the price war between Amazon/Google/Azure to keep prices in line.