順水人情

Simplified: 顺水人情

shùnshuǐrénqíng ㄕㄨㄣˋ ㄕㄨㄟˇ ㄖㄣˊ ㄑㄧㄥˊ

    • to do sb a favor at little cost

Character by character

Saying俗语俗語

Idiom惯用语 · In everyday use

Literally
a favour done downstream
Meaning
A favour that costs oneself no money or effort, like giving away something that comes free. Often slightly wry.

Sources