Massive Open Online Courses (MOOCs) have been promoted as a way to provide low cost education. However, I noticed that edX is now offering "edX Professional Education" courses which are considerably more expensive than previous edX MOOCs and comparable in cost to regular university courses.
Rice University is offering a course in "Basics of Energy Sustainability" for US$495. This is a four week course requiring two to four hours study a week (eight to sixteen hours total). That works out to between $31 and $62 per hour of study.
The course "ICT Sustainability" I run at ANU costs about $3,000. It is a typical twelve week long university course and requires eight to ten hours a week study (96 to 120 hours total). So this costs about $25 to $31 per hour, about the same, or less than the edXRice course. This is an on-line course which typically has twenty students and has a human tutor to assist.