As a college student, Ryan Grant bought used textbooks from classmates and resold them -- the textbooks, not the classmates -- on Amazon. He now runs an entire company, buying clearance items at Walmart and selling them on Amazon. This year's sales should top $8,000,000 and profits will be around $2,500,000. Golly gee!

This 28-year-old's company makes millions buying from Walmart and selling on Amazon

In a podcast on his Twitter page, Grant explains "How to start selling on Amazon."