I'm a Profit Center!

I'm continuing to teach a little bit in my retirement, and the third iteration of an intro econ class for MBA students starts June 24.  I have 20 students, who each paid something like $4K each in tuition for the course.  I'm being paid $3K to teach it.  So, I am, in fact, a profit center!  (Maybe I should give my lecture on the theory of the optimal bribe and see whether I can extract any additional consumer surplus from them.)  (It'd be better to extract some surplus from the university, but I can't quite figure out how to do that.)