Sanders is a Communist.
Communists don’t believe in money per se. They want to get rid of it altogether - rather than “paying”, one just takes what’s needed (never mind knock-down drag-out fights over what constitutes “need”, or why anyone would produce anything of value only to have it taken).
Bernie has made it very clear he has no interest in discussing “cost” of anything - a position only held to by Communists. When pressed, he resorts to hysterical flailing (both verbal and physical), quickly ended by giving just enough of a response to end the discussion under the circumstance.
Who will pay? To Bernie: everyone, with everything.
A commie wannabe at the moment; he hasn't started the killing yet.