unity comes with vs community. does i need to upgrade to vs pro to sell games as startup (little…) company ?
No.
You are permitted to sell your games using Unity’s free version (up to a limit).
You have to make a game before you can sell it.
You only need to upgrade to Visual Studio Pro if you no longer meet the terms of the license agreement.
https://www.visualstudio.com/license-terms/mt171547/
Basically you can use Community with up to five developers working concurrently in VS. After that you need Pro.
Or hit the million dollar revenue cap.
Stop laughing, it could happen. 
See this is why you need to read license agreements rather than simply asking on a forum. You don’t always get the full picture because sometimes the person responding - aside from completely misunderstanding the question - may not have covered every single thing of importance.
