In my case, graduating without debt was mostly due to the low tuition of New York state (SUNY) schools in the 80s. My tuition was $675/semester, and the minimum wage at the time was $3.35. That means in roughly 10 40 hour weeks over the summer, I could save enough for the year's tuition. Combine that with a 12hr/week job working in the computer labs and sysadmin'ing, and I could pay for my share of the rent & my car.
People talk about free tuition. But maybe we just need to get back to the middle ground of affordable tuition as measured by the minimum wage. Eg, put a cap on tuition so that it can't be more than X hours of work at a state's minimum wage.