How Much Would It Cost to Buy One of Everything on Amazon.com?

It would cost $12.86 billion USD. That's the answer on Quora from Kynan Eng, an expert on artificial intelligence and something called neuromorphic engineering--whatever that is. To sum up: he's a math guy who is much smarter than you or me. He's also the guy who once calculated how much money we spend rescuing Matt Damon over and over again.
Eng explains in great detail over at Quora how he arrived at $12.86 billion. He found a way to randomly generate a sample of Amazon.com products, then created a price distribution of them for his statistical model.
He did not include the price of shipping.