Most of North Carolina's hospitals are nonprofits. But many of them, especially the big ones, are making a fortune. During the Great Recession, their profits have stayed strong, and they've raised their prices. Top executives enjoy million-dollar compensation packages as they expand, buy expensive technology and build lavish facilities. Their customers buy the services before they know the cost, and they often don't understand the bills. And the hospitals enjoy a perk worth millions each year: They pay no income, property or sales taxes. In North Carolina's cities, these hospitals are piling up profits, along with billions of dollars in reserves.