Yes and no. There are definitely some courses on Coursera that are paid only. An example is Intro to TensorFlow with Google Cloud Platform. These courses are indicated by a small green $ symbol on the Class Central information page.
A big majority of the courses have some element of “free” — mostly the videos are free to watch but you need to pay if you want access to graded assignments and certificates. If you search for free courses on Coursera’s website, you will see a sticky note at the top of the search results explaining that lectures and non-graded material are free. However, Coursera still has many courses for which even the graded assignments are completely free. An investigation by Class Central discovered 1150+ Coursera courses that still completely free.