Contrary to what you may have been led to believe, I wasn't always a mildly crazed, mid-twenties geek; at one point, I was actually an eleven or twelve year-old, mildly crazed geek. Even then, though, I was learning some of the basics of economics, whether I realized it at the time or not. After all, even as a child, you still have to deal with things like supply, demand, and distribution of goods, even if you don't fully realize it at the time. Here's one story of what I gleaned from a Christmas decoration project during my elementary years.
First, a little background. I was part of the gifted program during my school career, from the time I was in elementary school on. In my school district, the gifted program focused on providing us ‘gifted' students with added challenges and opportunities in school, to help us learn and grow. In junior high and high school, this meant primarily getting extra assignments that we were expected to finish in order to graduate (not exactly the most rewarding situation for a young person), but back in elementary school, the gifted program was fun. We'd get out of class early on Wednesday afternoons, meet in the art room, and do fun activities that ranged from solving puzzles to making a short film (which, back in the pre-webcam and YouTube days when I was an elementary student, was a much bigger deal than it might be now).
One of the activities we did was to make and sell Christmas ornaments. As an introduction to marketing, manufacturing, and sales, it served pretty well. We got to see some of what goes into creating a quality product and how to sell it to other students. I gained quite a bit of knowledge about how to make Christmas ornaments, and learned that young students spending their parents' money were willing to buy home-made ornaments.

One of my biggest coups during my ornament creation career was when one of the other students left school before the sale. I was able to acquire his inventory (and just look at some of the vocabulary I picked up) for the cost of the supplies, and thus was able to sell more ornaments than I would have been able to make on my own. I learned that increasing your supply of salable materials can increase your profits. (Although, had my sales been worse than I expected, I would have been deeper in the hole than most of the others in the program, so it wasn't a risk-free transaction. That's an even more important lesson: taking added risks with the anticipation of higher rewards can sometimes back fire on you.)
One of my bigger regrets, looking back on the opportunity I was given, is that I did not attempt to advance my entrepreneurial ambitions beyond these yearly sales. I didn't try to set up my own business or create a product to sell. If I had gotten an earlier start thinking about my money, and how to make more of it, perhaps I could have gotten in on the first internet bubble. Alas, I didn't think to create this site ten years ago and make a fortune before I turned twenty, but it's never too late to relearn old lessons. Especially those that involve brightly colored ornaments.