I am looking for a version control system that will allow me to create any number of repositories and allow up to 30+ people to be able to access it as cheaply as possible. We can host this ourselves and backup to another server.
I have used Bitbucket for my own personal things, but I know, if I want more than 5 people they start charging.
We are going to be using this on a Linux system (Ubuntu/Mint) with people who may not have used Linux before. A front end GUI like Source Tree would be great.
If it's best just to use the command line then so be it (it should only make them better).
Stability, ease of use and longevity are important.