University of the People (https://www.uopeople.edu/) offers a tuition free CS degree program (both an AS and a BS). Many of the course materials are quite old (in some cases 5-10+ years), but this is really only a problem where specific technologies are concerned (for instance, there's a mobile applications class that covers Android 2.x). Many of the more general concepts will still apply.

Note that you do have to pay for exams, which are $100/class. This works out to be ~$4k for your entire CS degree.