It shall be unlawful for any person engaged in commerce in this state to sell or transfer motor fuel to itself or an affiliate for resale at another marketing level of distribution at a transfer price that is below cost or lower than the price it charges a person who purchases for resale on the same day and at the same distribution level, within the same market area, where the effect is to injure competition.
Ala. Code § 8-22-7 (1975)