It's a simple idea, but a radical one. Let people know in advance how much health care will cost them—and whether they can find a better deal somewhere else. With outrage growing over incomprehensible medical bills and patients facing a higher share of the costs, momentum is building for efforts to do just that. Price transparency, as it is known, is common in most industries but rare in health care, where "charges," "prices," "rates" and "payments" all have different meanings and bear little relation to actual costs. Unlike other industries, prices for health care can vary dramatically depending on who's paying.