I think the best way to educate children is to let them know where they are wrong. First of all, as a child of 12 years old, I don't think he should spend hundreds of dollars to buy game coins to play games. No matter how good your family is, you should establish a normal value for your child. 12 years old should be a time to play, but it should not be based on improper money. Secondly, children should not be allowed to invest in public transportation with game coins that cannot be used normally. Game currency is game currency, not to mention that one's own enterprise has closed down and cannot circulate normally in society. At least, this is a wrong behavior. At most, this is a disrespect for social morality. Finally, I think the solution is to communicate with the child first, tell him that this kind of behavior is not desirable (above), and warn him to coin normally next time he takes the bus. As compensation, parents can take money to buy game coins with corresponding prices for their children (you can pay less and don't indulge children of this age too much), so that children will agree with a high probability. Children must be given correct values!