when a shop sells items for less money than usual
I got this dress on sale.
我是在打折時買到這條裙子的。
available for purchase in a store, online, etc.
The video and book are now on sale.
視頻和書現在有售。
available at a lower price
I love that dress but I'm waiting until it's on sale before I buy it.
我喜歡那條裙子,但我要等到打折時再買。