Usually Coursera courses are free, but you need a visa card, you can use it within 7 days, then $ 49 per month
For example, I want to learn this course of google cloud
Actually, if I work hard, $ 49 per month is not very expensive, but most of them are sorry, do not want to spend.
There is 1 tip that applies to quite a few of these courses. Mechanism of coursera, some courses allow an audit (preview before learning, it still allows me to learn as usual, just do not grant certificates, that I do not care much about). When you click enroll, and see the audit is just like that, I see a lot of free courses like that.
I have listed the courses that I have studied