(Some at my previous day job once remarked that it would be cheaper to order me to do tutoring than to pay for a freelance English tutor, given the hourly equivalent of what Japanese salarymen my age made versus the typical price of an hour of English instruction in this neck of the woods.)
Edit to add:
That aside isn't quite so useful for folks not here. Let me hum a few bars: students at highly competitive suburban high schools, students studying for the LSAT, working professionals with gaps that are impeding their career growth, and middle class women who are filling a hole in their life through learning stuff all pay rather substantially more than 10 year olds who need help with multiplication.