On Monday Hillary Clinton became the latest Democrat to lay out her ideas for making college more affordable. The plan itself isn’t cheap, with its $350 billion price tag. Like some of her rivals for the Democratic ticket, Clinton wants to make college “debt free” for more students.  

Student loans are shaping up to be a central issue in this presidential campaign. Americans collectively owe more than $1 trillion in student loans, says Mark Huelsman with the think tank Demos, and a lot of them will be voting.

“The generation that’s really coming of age politically, the millennial generation, is the generation that has had to borrow the most, and for whom student debt really is the most acute crisis they’re probably facing, economically,” he says.

So what does “debt-free” actually mean? U.S. Sen. Bernie Sanders, of Vermont, has proposed eliminating tuition at public universities. The Clinton plan would give federal funding to states that make community college tuition-free and offer a no-loan option at four-year colleges. Under both proposals, low-income students would be able to use federal Pell grants to pay for living expenses. Former Maryland Gov. Martin O’Malley has also proposed making public colleges tuition-free within five years.