Supplier or cost prices are held as base or standard costs, branch or branch standard costs, or supplier specific costs. Cost prices can be derived from base pricing, standard costs or selling prices and marked up or down accordingly. Like all other prices, the user can create multiple cost price lines according to unit size and currency with conversion as required. Eight levels of quantity break discounting is provided, which can also be used to determine graded product pricing. Cost prices can also be calculated from multi-level Bill of Materials which is attached to an inventory item.