Deep-pocketed investors and veteran entrepreneurs are rushing to bet on Amazon’s third-party sellers. The stampede will change retail forever. : Business was booming for Adam St. George when he decided to shop around his four-year-old brand Angry Orange Odor Eliminator. Sold primarily on Amazon, his citrus-scented pet odor remover was racking up more than $2 million in annual revenue. Within hours of listing the operation on an online brokerage, St. George was inundated with phone calls. Planned time off to visit family in Ohio morphed into a marathon of negotiations with brokers, family offices and individual investors.