Between my senior year in High School and my Freshman year in college worked as a clerk at a discount store.
Then I parlayed a computer programming class I took in High School into a job as a computer operator, part-time, at the University I was attending (at 2.5 x minimum wage!). This was back in the early 1970s when computers were booming and anyone with any familiarity with them could find something in that field. Paid all my college expenses (except tuition, which my parents paid), and actually allowed me to save a few bucks.
Of course this was well before the ridiculous run-up in college costs, so you could work and pay for college.