Making public higher ed free would cost $60-75 billion a year, depending on whom you ask (The Atlantic ran an article recently that said $62B, and to his credit, Sanders’ own figure is the higher one of $75B). But we spend nearly 10 times that amount every year on war and occupation, for starters: the total cost of research and development for the F-35 alone is $1.5 trillion, and the damn thing isn’t even functional. The $120 billion that corporations avoid each year in taxes by keeping profits overseas would nearly cover it twice over. So the idea in itself is not some pie-in-the-sky utopian scheme, unless getting the ultrarich to pay taxes counts as utopian, and I don’t think it requires “running the numbers” in any complicated way to see that.
Sanders’ own proposal for covering it, which you never actually mention, is to levy a 1% tax on the trillions of dollars worth of speculative trading that is done on Wall St every year — even USNews, hardly a bastion of socialism, reported in 2013 that just a 0.03 percent tax (that’s 30 cents per $1000) would generate $350 billion over a decade, or $35B a year, so it’s certainly feasible, and something other countries like the UK and France are already doing (http://www.usnews.com/opinion/blogs/economic-intelligence/2013/08/21/a-wall-street-transaction-tax-would-be-good-for-the-economy-and-the-budget). In any case, his proposal, according to his website, says nothing at all about the need for a 5% growth rate to make it work (it would be great if you could provide a source for this), and either way I can’t see why that would be necessary, given all the things the federal government already pays for at far lower growth rates, and the obvious ways it could — if it cared to — raise further revenue to provide access to education for those who are priced out of it. It’s a simple matter of priorities.
But you’re right; he does have a thick accent, and “jabs his finger” a lot. And sometimes spits when he talks. So I feel you there.