I don't even remember how old I was, but it had to have been VERY young. I started off by selling "shiny pennies" to my siblings and cousins for quarters and then dollars soon after. My mother found out and grounded me and also cut off my allowance.
When I was fairly young I would get these "business life lessons" from my father, grandfathers, cousins and uncles mostly, sorta lil tips and tricks they would all talk about, on how to put things together or pick up on what people need. How to create urgency in supply and demand. This is the Jewish mentality that people who don't know what its like to grow up in NYC as a young Jewish kid. Its a lifestyle that never ends. The older you get, the more guys and sometimes girls you meet that share that same entrepreneurial fire hard-coded inside of you. I swear, the Jews (Americans, Israeli, Middle-Eastern, European, and Russian) and Italians in Brooklyn have this mindset that you have to experience in order to really see how things are done.
In early grade school I ran something like a commodities and loan sharking racket, although I didn't even know it at the time. You should know I attended a private coed Jewish prep school, so rules of kosher were strict as hell and everyone complied. From 1st grade until 6th grade, I would constantly find shit that kids in my school wanted and couldn't get either on the school grounds or in general. Everything from Warhead candies, blue Blowpops, Baseball card for flipping, Gold NBA cards (Shaq rookie cards), Slap Bracelets, chocolates from Israel, Pop Rocks, Trapper Keepers, Inkwell pens, whatever.. And for those that didn't have the cash on hand for it or couldn't trade for something of value, they would be put onto a sort of payment plan, where at the end of the week (when most kids had their allowance) I'd have one of the bullies hit them up for the amount. It wasn't just in school either, the older I got, the more ground I covered, and spread out to synagogue/shul, sports practices, other schools, etc. Even during Chanukah, when the boys in each grade would play driedel religiously in a corner of the recess yard or in the boys bathroom for dimes and quarters, I had two driedels that had shaved bottoms so it would almost always fall on Gimel (the jackpot letter), but they were shaved down so that you couldn't even tell if you rubbed your finger over it or looked at it. Made fucking bank. After 6th grade though, like during 7th and 8th grade I didn't really do shit, because my goal was to push the teachers as far as I could and get suspended as often as possible to avoid going to class.
High school was a whole new ball game, because that's when I met other guys, mostly Jews and Italians from other schools and neighborhoods that had been doing things just like I used to, but were already putting their chops together and graduating onto bigger and MUCH more profitable areas of interest. Its the ages of 13-18 where you truly make your bones and do as much fucking up as possible until you become whatever it is you were meant to do. Saw tons of friends and foes die, get killed, overdose, go to jail/prison, skip town or the country and never come back, etc. Its no joke.
Life is just one big game I suppose. The winners get to see it through and hopefully die on their own terms, and the losers, well, go out early. It is what it is.