Not exactly illegal nor in highschool. However, after elementary school my friend and I would take acorns from outside, paint the tops with nail polish, add a smiley face with sharpie and call them "Nutty Buddies". We would make them homes with multiple levels out of cardboard out of my friend's garage. Neighborhood kids that lived nearby would come by to her house to buy custom houses and Nutty Buddies after she began selling them at school. This was around the time Silly Bands came out, so our Nutty Buddies sold just as rapidly to kids. It was a way better idea than a lemonade stand. Eventually, we got caught and we were banned from selling them at school, unfortunately.