Google Code Project Hosting lately modified CodeMirror to permit quick in-browser editing of code inside a repository. This appears very helpful! Regrettably not every one of my projects are free.

Are there more DVCS (Mercurial or Git) hosts which have this feature but support closed-source projects? Particularly, free could be nice (since Let me host personal projects by using it and have the ability to tweak them within the browser) I am a student, therefore if there is a discount or free mode because of that, that's awesome too!

Github can perform that. There's a “edit this file” button alongside each code viewer.

See also the “Edit Online” section on Features / Hosting.

Take a look at http://bitbucket.org for Mercurial.