A large cost factor for educational institutions is staffing them. Schools have maintenance costs (cleaning, basic repairs etc.) and service costs (food service, security, help desks, etc.) that require a low level of know-how, and low time commitments. Instead of staffing employees and hiring third-party contractors to serve these basic needs, students can be mandatorily tasked with caring for their own campus.
In Japan, students clean their own classrooms and school grounds, as well as serve one another food, as highlighted by the image and video above. These activities reportedly ingrain appreciation, pride, and a sense of responsibility in students that prepare them for, and stay with them through, the working professional world.
A software system could be developed that replaces schools' current class registrars, with a class registration system including both class options and task options that students can choose from for their following semester. The system would, through what I would imagine to be a complex set of algorithms (or functions of that nature), assure that both maintenance and service tasks will be equitably assigned (and rotated) amongst the student body so as to eliminate those costs. Cost savings on these fronts will also be achieved in other ways than just eliminating (at least in large-part) current salaries or contracts. Incoming students each year will learn about the operational needs and functions of their school, and offer fresh perspective on what can be done to be more efficient- a feedback loop that can be difficult to develop when the same people remain in the same position for years at a time. The cost savings for schools can be applied towards subsidizing all students education.
It's likely though that this alone will not be sufficient to eliminate tuition and housing costs. Take NYU for example. Tuition and housing are roughly $70,000 per student/per year. Multiply that by the number of undergraduate students (roughly 25,000), and we get roughly $1,750,000,000 (1.75B USD) in earned income to NYU. Let's account for financial aid and chop off $750,000,000. The likelihood of keeping NYU clean and serving students food costing $1,000,000,000/yr are slim to none (but not even slim at all).
What if the cities and towns these colleges are located in provided the housing for students? At NYU this would knock roughly $30,000/yr off of that $70,000/yr cost. But what incentive would the city have to do so? Well- what if students had the option to stay at their college for one year after receiving their undergraduate degree, conducting research on the city's issues? These issues could range from solving issues of homelessness, criminal recidivism, drug addiction, equal educational opportunity, etc.
Any reduction in a schools level of financial aid funds needed can be repurposed to serve as operational grants to pay for salaries of administrators and educators, which can further reduce the cost of tuition.