You can get most Coursera courses for free by clicking on “Audit” link. This way you can access course content but without certificate.
First, click on Enroll for Free, then click on Audit the course (if you cannot find audit link, go below of this article) . As you see in this image:
If you cannot find Audit link, then maybe you are on a specialization page. A specialization is a set of courses.
To get the courses in the specialization for free, click on Courses in the specialization page, and you should go to each course and click on Enroll for Free, and then you will be able to see Audit the course link.