How to say great deal (slang) in Korean
Korean: 혜자[ hye-ja ]

Meaning
(혜자) is slang for something that gives you a lot for the price, so it feels like a great deal. People often use it for food, sets, tickets, or stores when the amount or quality is better than expected. It is a casual word, so it is best in everyday conversation with friends.
Example sentences
편의점 도시락은 진짜 혜자야.
The convenience store lunchbox is really a great deal.
친구가 이 영화 티켓이 혜자라고 해.
My friend said this movie ticket is a great deal.
학식 메뉴 오늘은 혜자네.
Today's school cafeteria menu is a great deal.
친구가 이 카페 세트가 혜자라고 했어.
My friend said this cafe set is a great deal.