Is the stepik platform free?

Question

Python

I know the basics of python. I want more, I found the stepik platform, as they say it is free. Is this true, will it come out in the middle of the training: 'Pay a lot of money or get out of here'. And what about the quality of the courses?

Answer 1

For a long time I took courses in python from the Institute of Biotechnology, it seems. The best courses I've come across. Everything is free.

Answer 2

Passed in due time (in 2015) the course "Discrete structures" there. Everything was free

Answer 3

went through the python, what to say - it will go to start ..
link but for more serious things you need a more serious approach (for example, cython). But it was free...