Bakend API for Android apps

What is the most common language/platform for developing bakend REST API to be consumed by an Android app?

I want to develop a few Free Android apps that would consume REST (JSON) services from my own custom API. Part of the consideration is that the hosting for such API should be cheap, as in on a shared Linux or Windows host. I researched cloud hosting, and it is costly.

I can write a Web API 2.0 on .NET and host it on IIS on a shared hosting. But I could not find any definite answer as to what language or platform is commonly used. Is it JAX? if so - how and where does it get hosted?

Is it something else?