Mom and Dad, bless 'em.
If we happened to run into financial difficulty however (and my schooling became a burden) then I'd end up financing it at least partially myself, although it might be difficult to convince them to do it. I do pay for some of my books though.
Note: As one of the "all for free" kids, I too understand exactly how much it costs, which is one of the reasons I show up for the majority of lectures. Yes, I
could do almost as well without showing up, but then it feels more like a waste of money and opportunity.