Definition
to provide an item you possess as partial payment towards purchasing another item, particularly a newer version of the same type
用…折價換購（特別是同類型的新商品）
She decided to trade in her old car for a new one.
她決定用她的舊車折價換購一輛新車。
You can trade in your tablet for the latest model.
你可以用你的平板電腦折價換購最新型號。
He traded in his old TV for a larger one.
他用他的舊電視折價換購了一台更大的電視。