Having just babysat 4 nieces and nephews all weekend who are yet to learn the cost of living, I related money to fun with the eldest first (a 14 year old beautiful girl who of course feels she needs to spend $14 on hair straightener). We worked out this was 3.5 weeks of her pocket money (which shocked her) and ensured she didn’t waste the “beautifying product”.
Of course this can be used by any adult. Work out your hourly rate (after tax and Super / 401K contributions) and then compare your spending. For example, if you work 40 hrs per week for $400 clear into your account, then your rate is $10/hour. If you spend $30 you’ve just worked 3 hours for that purchase.