(a) It is unlawful for any refiner, distributor, producer, or transporter of petroleum products engaged in business in this state, either directly or indirectly, to discriminate in price between purchasers of petroleum products of similar grade and quality.
(b) Nothing in this section shall prevent differentials that only make allowance for differences in the cost of manufacture, marketing, transportation, sale, or delivery resulting from the different methods or quantities in which the commodities are sold and delivered to the purchasers.
(c) Nothing in this section shall prevent persons engaged in selling goods, wares, or merchandise in commerce from selecting their own customers in bona fide transactions and not in restraint of trade.
(d) It is unlawful for any wholesaler or reseller of petroleum products to sell at retail level for less than four cents (4¢) below his or her wholesale price to wholesale accounts who resell at retail in the same market area.
(e) Nothing in this section applies to the purchase of petroleum products for their own use by state and local agencies.
(f) The provisions of this section only apply to producers, refiners, or wholesalers whose total production, gasoline refining capacity, or sales volume at the wholesale level is fifteen thousand gallons (15,000 gals.) a day or more.