California Code, Business and Professions Code - BPC § 17041

Nothing in this chapter prohibits locality discriminations which make allowances for differences, if any, in the grade, quality or quantity when based and justified in the cost of manufacture, sale or delivery, or the actual cost of transportation from the point of production, if a raw product or commodity, or from the point of manufacture if a manufactured product or commodity, or from the point of shipment to the point of destination.