Coursera is an online education provider that offers online courses, popularly known as “MOOCs” or Massive Open Online Courses, from top universities around the world. Currently, Coursera boasts an active catalog of 2,700 online courses created by these partner institutions.
Coursera courses consists of pre-recorded video lectures that you can watch on a weekly schedule or when it's convenient for you. They also have student discussion forums, homework/assignments, and online quizzes or exams.
Generally speaking, Coursera courses are free to audit (i.e. watch videos) but if you want to access graded assignments or earn a course Certificate, you will need to pay. An investigation by Class Central discovered 1150+ Coursera courses that are still completely free.
Many of the Coursera courses are part of Coursera Specializations, a micro-credential offered by Coursera. Specializations consist of a sequence of courses and for some Specializations the last course is a Capstone project. If learners earn a certificate for each course in a Specialization, they will earn a Specialization certificate.
Usually Specializations are geared towards in-demand skills in business and technology. Coursera has launched over 250 such specializations.
If you are not clear on how how to sign up for Coursera courses for free, here is a guide from Class Central: A Guide on How to Sign up for Coursera Courses for Free
If you want a certificate but cannot afford the cost, Coursera offers financial aid to needy applicants. Here is more information from Coursera: https://learner.coursera.help/hc/en-us/articles/209819033-Apply-for-Financial-Aid