A friend and I did about 30k in profit at age 15 in '02-'03, and it would have been way higher if we weren't having issues with merchant accounts. I doubt it would have gone into the millions, but easily 100k-200k.

Finding a market and executing on an opportunity isn't that difficult of a thing to do - the trick is finding one within your grasp. This was virtual goods, so it required almost no upfront capital and very little development and maintenance costs. It's no massively-scalable startup, but when your goal is just to create a profitable lifestyle business, it isn't actually that complicated.

I remember lots of stories of people selling things on ebay at a young age back in the day. I'm pretty sure some must have made more than $1MM in revenue.

Recently there was a story about a 16 y/o who's converting a sports car to electric and runs a CAD business that seems to be doing pretty well.

Edit: I just dug up the car conversion thread I mentioned. This kid is making amazing progress: http://www.s2ki.com/s2000/topic/975497-wait-that-isnt-an-f20... (that's the last page of his forum updates)

Here's a couple:

http://www.forbes.com/2008/02/09/teen-millionaires-startups-...

Only one immediately jumped to mind for me: http://en.wikipedia.org/wiki/Ashley_Qualls (that entry doesn't talk about revenue but news stories did at the time)