"Shark Tank" star Barbara Corcoran.Jin S. Lee/Business InsiderBarbara Corcoran once made over $1.2 million by selling 88  apartments in less than three hours.The "Shark Tank" star modeled her strategy on a puppy sale she watched as a child.The real-estate mogul learned that artificial scarcity can sell both puppies and properties.Barbara Corcoran once sold 88 lousy apartments within three hours, making her $1.2 million, by cribbing from a puppy sale she witnessed as a child.The real-estate tycoon and "Shark Tank" star was tasked with selling the apartments in the early 1990s when interest rates were a sky-high 18%.