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.
This seems to be the cheapest accredited option, use University of the People to get any kind of undergrad, then can pay for a masters in CS somewhere else. (Too bad uopen doesn't have an applied math undergrad, then the material being dated wouldn't matter).
There is Athabasca U in Canada which offers a fully online, and accredited BSc in CompSci or Applied Mathematics, and the only requirements are 16+yrs old (no transcripts or even highschool grad needed) but the fees are $900CAD or so for 3 credit courses and you need to complete 120 credits so ~$35k for an undergrad ($27k USD). http://www.athabascau.ca/programs-courses/ whereas you could do Upeople, obtain an undergrad and pay for Johns Hopkins MSc for the same cost.
There's also been reports that Athabasca U is having funding issues at present, for those looking at this option (which is the only option in Canada for online in this field that I've found.)
Note that you do have to pay for exams, which are $100/class. This works out to be ~$4k for your entire CS degree.