You know, this kind of stuff is part of being a kid. When I was in first grade, my next door neighbor and I went into a water-selling business (think lemonade

You know, this kind of stuff is part of being a kid. When I was in first grade, my next door neighbor and I went into a water-selling business (think lemonade stand without the lemons) that failed miserably. My next venture was substantially more successful. Living in France, we had sticker albums associated to stories. A new movie would come out (for example, Star Wars) and shops would sell the album and sell sticker packs separately (each pack sold for the equivalent of about a buck and had 5-6 stickers in them). Each of the stickers were numbered and you would put them in your album to gradually uncover the story. Thing was, there always seemed to be some stickers you were missing and couldn't find in the pack. So I first set up a marketplace where people could sell me their unused stickers for 1 cent and I would sell the sticker someone was looking for for 50 cents. I don't remember any parent pressure in the matter (mostly, my parents looked at this as kids being kids) and I learned a lot about supply and demand in the process (including getting stuck with tons of worthless stickers at some point :) )