In his 2020 run for president, Democratic Senator Bernie Sanders has a proposal to make college free.br He also wants to pay off all outstanding student debt.br How would he make it happen? His solution is pretty straightforward. br Business Insider explains, "Since Main Street bailed out Wall Street during the financial crisis, Wall Street should now return the favor."br It would mean a "0.5 tax on stock transactions, a 0.1 tax on bond trades, and a 0.005 tax on derivatives transactions.