It's often the most innocuous of products that bring in the big bucks. I don't personally wear glasses that need to be taken on and off, so little did I know there was a gaping hole in the market just waiting for ReadeREST to fill. But if there's anyone I'd trust to recognize a product that people need (or at least think they need), it's Lori Greiner, "Queen of QVC." Greiner saw the small magnetic glasses holder as a product millions of people would see a use for, with tons of room for mark-up. And she was right! After an initial investment of $150,000 for 65 percent, she and QVC have helped bring inventor Rick Hopper's sales to over $8 million in the last two years, as he told CNBC.