Default pricing for cost and sell prices of catalogues is configured on the Supplier List screen (Discounts & Margins button).
In addition you can configure different types of special discounts and special prices that override those defaults. This is an overview of the different special price settings. These settings are all set in the Customer List screen (Account Details tab) so apply to a selected customer
Discount Bands - Allows for setting selling price discounts on multiple catalogues, and 2 order level discounts.
Discounts - Allows for discounting the selling price based on a catalogue
Prices - Allows for setting special cost and/or selling prices
Suppliers - Allows or setting a different cost price discount % and/or selling price margin %. (Will override those set in the Supplier List).