From Sanders’ website:

Here are the six steps that Bernie will take as President to make college debt free:

MAKE TUITION FREE AT PUBLIC COLLEGES AND UNIVERSITIES.

This is not a radical idea. Last year, Germany eliminated tuition because they believed that charging students $1,300 per year was discouraging Germans from going to college. Next year, Chile will do the same. Finland, Norway, Sweden and many other countries around the world also offer free college to all of their citizens. If other countries can take this action, so can the United States of America.

In fact, it’s what many of our colleges and universities used to do. The University of California system offered free tuition at its schools until the 1980s. In 1965, average tuition at a four-year public university was just $243 and many of the best colleges - including the City University of New York - did not charge any tuition at all. The Sanders plan would make tuition free at public colleges and universities throughout the country.

So if we’re going to be nit pickers about it, he’s saying it will be free for everyone who gets accepted into a public college, i.e. it’s free.

BTW, I went to the University of CA in the 1970s and it most certainly wasn’t free. It was cheap, but not free. Community colleges back then were tuition free.