In English, "大减价" can be translated to "big discount" or "major markdown." This phrase comes from the Chinese word "减价," which means "to reduce the price of something." Here are some examples of how you can use "big discount" or "major markdown" in English sentences:

The store is having a big discount on winter coats.

I got a major markdown on my new phone.

Don't miss out on our big discounts on furniture.

I'm looking for a major markdown on a new TV.