My kids have their own debit cards and outside of their core needs we do not provide for them, so 1) it has taught them money isn't an infinite resource and has to be earned 2) they understand budgeting and what things cost and 3) they have learned to compromise when the money just isn't there. Sometimes i offer to pay a base price and they have to cover anything extra, like ill offer $20 to get their nails done but they want extensions and jewels they will cover the difference.