Definition
to be a purchase that is/ is not justified by its cost
合算的／不合算的買賣
This smartphone was a good buy during the big sale!
這支智慧型手機在大特價時買很划算！
These shoes are cheap, but the quality is poor, making it a bad buy.
這些鞋子雖然便宜，但品質很差，買得不划算。
Although the price is low, the performance of this TV is excellent, so it's a very good buy.
雖然價格低，但這台電視的性能非常好，所以非常划算。