money pit
US /ˈmʌn.i pɪt/
UK /ˈmʌn.i pɪt/

1.
金食い虫, 無駄な出費
something that costs a lot of money to operate or maintain
:
•
That old car has become a real money pit.
あの古い車は本当に金食い虫になった。
•
Buying that huge house was a mistake; it's been a money pit ever since.
あの大きな家を買ったのは間違いだった。それ以来ずっと金食い虫だ。