There may be some payments needed to receive accreditation after completing your MOOC (usually under $100). However, sometimes graded assessments can also be hidden behind a paywall. Besides certificates, other MOOC components may be hidden behind a paywall — for instance, graded assignments. There is the occasional MOOC that's completely behind a paywall (even though they're not technically "open"). You can audit the courses for free though, which means you can access all of the course content but not complete any assignments. This is great for those who are interested and looking at increasing knowledge but don't need the accreditation. If you're interested in financial aid, there are also options for that. Read more about Coursera's payment options here.