Most of the easy money has already been made on Carvana stock -- and now it costs too much. It's starting to look like Carvana (CVNA -4.18%) stock is going to survive its near-death experience. One year ago, Carvana wrapped up its worst year ever, losing $1.6 billion despite booking a record$13.6 billion in sales. Burdened with $6.1 billion in long-term debt, and another$1 billion in long-term lease obligations, this used car dealer's future looked grim. One year later, however, Carvana stock has soared 1 ...