We are really sad with this change that require credit card to have a free account.
We are a small startup here in São Paulo (Brazil) that is using C9 to help students prepare themselves to internships in software development. We are creating a video course with many exercises. Those exercises are meant to be done by the students using C9. We already have 7 students testing our course and everything is (or was ) going very well.
We have already made a bunch of videos using C9 to show on practice the concepts being taught in order to make the students comfortable to use C9. We will launch our course in 1 week and a half and requiring a CC completely kills what we are creating because the majority of our students don’t have a CC.
As software developers know, having the same development environment for every developer is much more productive and easier to work. We believe this also happen in a learning environment. We have given the same course not using online tools like C9 and we always had problems with university computers, students notebooks, even trying to run VirtualBox VMs in different and old machines results in trouble. Furthermore, this allow students to use a tablet, mac, windows, linux or whatever to learn. They just need the browser to watch the videos and do the exercises.
The university account is not possible for us, it is too much expensive after converting USD to BRL considering the amount we intend to charge for our course.
I really hope to hear good news from C9 in the next days about this.
In the meantime, we will try to find a pre paid credit card like @Nezteb suggested.