Except for Professional Education, Boot Camps, and Executive Education courses, there is no cost for taking edX open courses when you enroll in the free audit track, which does not offer certificates or provide graded assignments.
However, if you want to be able to earn a certificate for a course and complete assignments, there is a fee that will vary depending on the course. The fees for the verified track usually range between $50 USD and $300 USD. You can confirm the price of an edX open course if you click Ways to Enroll on the course enrollment page.
Please note that some courses (such as Boot Camps, Professional / Executive Education, and Bachelors / Masters) may have a higher price.
The fees for upgrading to the verified track or enrolling in a Professional Education, Boot Camp, or Executive Education course are the only charges on edX. There are no other fees associated with edX courses.
You can find more information about the different certificates offered by edX: What types of certificates does edX offer?
edX has a financial assistance program for a discounted fee to help learners who demonstrate financial need to earn verified certificates.