Several years ago I started a hip-hop jewelry ecommerce store. My most popular products were “grillz.” For the unfamiliar, those are the shiny teeth you see a lot of rappers wear. I shipped tens of thousands of these grillz to customers from all over the world.The idea to start selling these products came to me one night, over the course of just a few minutes, when I overheard people at a concert saying how they wished they could buy a set. They complained how the process to acquire them was too slow and expensive. That’s when the lightbulb went on.

Source: How I Came Up With a Million-Dollar Ecommerce Idea in 20 Minutes