What child has $500? "Whales" are adults. (Usually, specifically, they are people in high-stress/high-reward jobs, like finance, who want to release their stress by throwing out their rewards. Same as casinos.)
Children use their parent's phone, there were a spate of cases recently where children's apps had a ton of expensive in-app purchases and hooked children ran up $2000-$3000 Bills
This happened to a friend of mine. Her grandson only 4 was able to make many in app purchases to the turn of hundreds of dollars.
They're mostly addicts who still have room left on one of their credit cards.