Supplier prices are not publicly available, therefore only Suppliers are entitled to access.
You won't see any Supplier price in your response if you are not authenticated and your user does not match proper access rights.
Price paid by Musement to the supplier. This field is returned only when requests are made by a Client Application that has supplier's role.
supplier_price = (supplier_original_retail_price - service_fee) - commission%
supplier_original_retail_price = (supplier_price + commission%) + service_fee