Never anything like that. I usually capitalized on whatever fads were around. I went to middle school in the early 90s so it was things like those MagicEye books. I'd buy a box of them from the publisher and sell them for retail price at ( back then ) 200% markup.
Hey I used to do the same thing! Yo-yo's were a fad when I was in primary school, so I'd buy the from the flea market and sell them at a mark-up at school. Also, bulk lollies -- absolutely brilliant for making change at school. When we had a "paper hornet" war, I sold prepackaged "ammo" kits!
That line just made me think of the guys our our middle school who would buy up bulk soda and sell them for $1 or $2. But getting in on toy/widget fads is much smarter, though with a higher risk of the fad blowing over while you had money sitting in inventory.
I'm amused that that's the first thing to come to mind. I certainly went to schools with plenty of more criminal elements, but the first thing to come to mind was definitely the kids who marked up candy bars and sold them for pocket cash.
"Lütke enjoyed selling—as a boy in school, he’d made some money buying items in bulk and selling them at a mark-up to other school kids."