Massive Open Online Courseware (MOOCs) are University courses made available over the Internet without charge to a very large number of people.
Coursera (You have to search specifically for the free courses)
Udemy (You have to search specifically for the free courses)
More online courseware
List of all MOOCs
I can personally vouch for the Resilience Course provided by EdX and the 'Good Brain Bad Brain' course provided by University of Birmingham via Future Learn. Great way of connecting with others (all over the world) who are interested in the subject, too.