Photo: Ahmet Serdar Eser/Anadolu/Getty Images In August, Dr. Mehmet Oz ’s official YouTube account posted a video titled “Get $0/Month Medicare Coverage: What You Need to Know,” in which Oz lays a sales pitch on his viewers. “Which of these items can you get for zero dollars?” he says, pointing to images of a coffee cup, a pack of gum, and a newspaper, as if quizzing a toddler on the pictures in a children’s book. “Or how about a health-insurance plan?” he says. If you’ve ever watched daytime