two for one

• 买一送一

two for one的用法和样例：

例句

1. They're doing two for one admission to this show.
   这个展览的门票是买一送一的。
2. As a matter of fact, the salesmanship of "two for one" is a good way of advertising.
   买一送一的推销术，实际上是一种不错的广告。