Along with the fact that Finland features more play than memorization in its curriculum design, education is essentially free at any level.
Only a small number of independent schools exist in Finland, and even they are all publicly financed. None is allowed to charge tuition fees. There are no private universities, either. This means that practically every person in Finland attends public school, whether for pre-K or a Ph.D.
via What Americans Keep Ignoring About Finland’s School Success