得dé不bù偿cháng失shī

Literal: what is gained does not make up for what is lost
Figurative: To come out behind on balance: what you gain doesn't make up for the effort, the money, or the harm it cost you.

Where does 得不偿失 come from?

The phrase is built like a set of scales: 得 ("what is gained") on one side, 失 ("what is lost") on the other, with 偿 ("to make up for, to repay") in between to say that the first does not cover the second. The origin usually cited is a line by the Song poet Su Shi, in a poem addressed to his brother Su Zhe, where the sequence 所得不偿失 — "what is gained does not make up for what is lost" — already appears. The four-character form settled from there. Today it is used to judge decisions: a deal, a renovation, an effort that costs more than it returns.

Source (出处): 苏轼《和子由除日见寄》

How is 得不偿失 used? Two examples

为wèi了le省shěng那nà几jǐ十shí块kuài钱qián跑pǎo这zhè么me远yuǎn，真zhēn是shì得dé不bù偿cháng失shī。
Going that far just to save a few bucks really isn't worth it.
熬áo夜yè赶gǎn工gōng把bǎ身shēn体tǐ搞gǎo垮kuǎ了le，这zhè样yàng做zuò得dé不bù偿cháng失shī。
Pulling all-nighters to hit the deadline and wrecking your health that way costs more than it's worth.

In Wanyu, all 400 chengyu have audio on every sentence, and you can save them to your decks and review them with spaced repetition. Free.