Detailed Discount For Vendors

Hello all,

I have a question.

I am looking for a detailed discount plugin that can be used for CS-Cart Multi Vendor Ultimate. Vendors will be able to make discounts on their products.

Exemple:

The regular price of an item is $20. 1 purchase will cost 20 dollars, 2 purchases will cost 19 dollars, and 3 purchases will cost 18 dollars. Or is there an add-on that will pay $20 when you buy 1 but give a % discount on purchases of 2 or more?

I will be glad if you provide information.

Thanks