‘Cost an arm and a leg’ is an often-used phrase to describe anything that costs a person much more than they expected they would have to spend.

我買的飛往歐洲的機票，價格高得嚇人。

買那張飛機票，竟然花掉我的一手一腳 (cost an arm and a leg)？這樣的形容實在很生動。平常，我們只會說「花去我荷包的一大半」之類的話！