If you're good at standardized exams, test prep teaching is great. I did that on the side for 7 years, and I plan to go back when the kiddos are older. I had to score at least 90th percentile on a diagnostic version of any exam I taught (SAT, LSAT, GMAT, and GRE). Paid prep time, $20+/hour for teaching - the teaching rate goes up as you accumulate high reviews from your students. I'd sign up per course, which would be anywhere from 8-13 sessions, 1-3 evenings a week, so no long-term commitments. Tutoring was super-flexible. If I had no extra time, I just didn't take any classes. When I wasn't working otherwise, I picked up over 20 hours a week.