Open source and communities. That is what social coding is about.
Today there are several free options and here are some of them, listed alphabetically:
- Bitbucket (Git and Mercurial)
- GitHub (Git)
- Gitorious (Git)
- Google Code (Git, Mercurial and Subversion)
- Sourceforge (Git, Mercurial and Subversion)
As can be seen, all of the above examples support primarily Git, and in most cases also Mercurial and Subversion. In addition to what is supported as the repository type hosted at the server, the client tools can differ, for example Subversion can be used via Git tools.
Some of the many graphical interface tools, listed alphabetically: