Selena Gomez has topped the first-ever Instagram rich list, earning a whopping $550,000 per post. The singer is also the most followed person on the app, with 123 million followers. Reality star Kim Kardashian West and soccer player Cristiano Ronaldo are second and third on the list. The list was created by Hopper HQ, an Instagram scheduling site, using its internal data and public information. Mike Bandar, co-founder of HopperHQ