money doesn't grow on trees idiom saying
（提醒别人花钱时要谨慎）钱可不是从树上长出来的，钱可不是从天上掉下来的
said to warn someone to be careful how much money they spend, because there is only a limited amount
"Mum, I'd like a new bike." "I'll have to think about it - money doesn't grow on trees, you know!" “妈妈，我想要辆新自行车。”“我得想想看──你知道，钱可不是从天上掉下来的！”