Server side server for Browser MMORPG?

Hi guys, I'm sorry for asking this question; I know it's been asking 1000 times. But I'm at a loss.

I have one copy of Unity Pro and I want to make a browser MMORPG, with Mysql support, but I don't know what to use to host it.

Should I make my own C# server app? I don't have money for smartfox right now :(

Thanks guys, shared info is much appreciated.