When I was a child growing up in BP, my parents could not afford full tuition, BUT THEY PAID IT ALMOST ALL THE TIME, BEFORE VACATIONS, BEFORE NEW CLOTHES, BEFORE NICE CAR. They yeshiva had mothers coming to school to ‘serve lunch’. I still remember my mother coming once or twice a month to do it.
WHATS WRONG IF PARENTS HELP THE SCHOOL? get rid of some of the custodians and have them ‘sweep”. (Chas v’shalom, i wont ask you to clean toilets’) Your wife used to teach? Let her sub when a teacher is out.