They're good customers who always pay on the nail.

他们是好主顾，付账从不耽搁。

《牛津词典》

We have to pay on the nail before we can leave with the goods.

我们必须当场付款，才能拿走货物。

youdao

We have to pay on the nail before we can leave with the goods.

我们必须当场付款，才能拿走货物。

youdao