A price margin refers to the discount rate offered by a brand to its partners. This margin can be adjusted for the entire shop or at the individual product level.
For example, a supplier has decided to give a 40% discount (price margin) on a product with the retail price of $10. It means you will import the product at the unit cost of $6 and set your own retail price. Regardless of the price at which you decide to sell the product in your store, you still have to pay $6 + shipping costs (if any) to the supplier.