MOOCs are Massive Open Online Courses run via distance learning and are completely web based. They are usually free to complete and are offered by some of the most prestigious educational institutions in the world such as MIT, Univeristy of California Berkley and Stanford University.
Any cost involved usually occurs if a person wishes to receive certification for completing the course, however, this is not usually a necessity making completing the course free.
Here are some general links to sites offering a range of MOOCs;
Here are some Psychology based ones.