Yoga studios are as ubiquitous as Starbucks, but it’s rare to find one that charges little more than a venti latte for an hour-long class. Enter Adam David’s Viva Vinyasa!, which opened this month and costs just $10 a session. To keep fees down, David, late of Crunch and Equinox, set up shop in a clean (if not exactly glamorous), lunch-break-convenient space on the sixth floor of a commercial building in midtown. The yoga itself takes a similarly no- frills approach, focusing on results-driven cardio workouts instead of om-heavy meditation (226 E. 54th St., nr. Third Ave., Ste. 600; 646-692-8185).