I agree that the "free college" issue was not laid out clearly enough. In reality, many countries offer free public education at the college level, it's not a ridiculous proposition. It's a worthy cause as long as the programs being subsidized lead to more capable and, eventually, more affluent American work force that would boost the economy.
Ideally, Bernie's platform would offset the cost of some free higher education by closing corporate tax loopholes, releasing non-violent drug offenders from tax-funded prisons and jails, and significantly reducing military spending.