I received < $13/h with an MSc. for teaching ESL in the private sector. (I would go to different businesses and run ESL classes.as a subcontractor for a language school). At the Universtiy level, I would receive just over $14/h if I were working as an instructor with an MSc.
Teaching high school was, by far, the most difficult job I've ever had. I worked around 12 hours per day and tried to take Saturday mornings for myself. I often had too much work to do that, though. As a science teacher, not only did I have the regular prep and marking of the regular teacher, I had to verify and set up the labs myself as well as mark lab reports. While teaching grade 9 science, I could physically feel my energy draining as the hour passed.
I was obliged to teach subjects I've never studied (eg meteorology) so some time had to be spent on my own studies.
Finally, all those summer holidays people envy had to be spent on finding and preparing resources and general lessons as well as catching up on recent science discoveries.
