I'm thinking about selling online?

I'm leaning towards using amazon to sell my items, I already have the wholeseller and I only need to know the risks involving taxes, am not looking to become a millionare but I dont want to get arrested for not reporting X amount of money (if somehow the irs found out about how I get some part of my income) ...this would be only kind of like a side opportunity to make extra cash because of course I want to keep my current job, does anyone know the risks? or how to report my earnings. any help will be greatly appreciated