Section 1501 - Rates of service charges(a) A seller may, in a retail installment contract, contract for and, if so contracted for, the holder thereof may charge, receive and collect a service charge measured for a period between the date of such contract and the due date of the last installment and calculated for that period according to the actuarial method of computation or by application of the United States rule at a rate which is agreed upon by the seller or holder and the buyer.(b) Notwithstanding the rates provided for in this section, no issuer of a credit card primarily engaged as a seller or distributor of gasoline shall be permitted to charge, receive or collect a service charge in excess of fifteen percent (15%) simple interest per annum on unpaid balances.(b.1) Notwithstanding the rates provided for in this section, no bailor or lessor of goods shall be permitted to charge, receive or collect a service charge in excess of eighteen percent (18%) simple interest per annum on unpaid balances in a contract under which the bailee or lessee: (1) agrees to pay as compensation for use of the goods a sum substantially equivalent to or in excess of the value of the goods; and (2) has an option to become the owner of the goods for no additional or nominal additional consideration. This subsection shall not apply to a rental-purchase agreement as defined in 42 Pa.C.S. § 6902 (relating to definitions).(c) A minimum service charge of fifty cents (50¢ per month may be made for each month if the service charge so computed is less than that amount; such minimum service charge may be imposed for a minimum period of six months.1966, Special Sess. No. 1, Oct. 28, P.L. 55, art. V, § 501. Amended 1982, March 25, P.L. 199, No. 68, § 5, imd. effective. Reenacted 1985, March 1, P.L. 2, No. 2, § 1, imd. effective; 1988, Feb. 26, P.L. 78, No. 15, § 2, imd. effective; 1989, July 11, P.L. 573, No. 57, § 2, imd. effective; 1991, Feb. 21, P.L. 1, No. 1, § 1, imd. effective. Subsecs. (a) and (b) reenacted 1994, May 27, P.L. 253, No. 39, § 2, imd. effective. Amended 1996, Dec. 20, P.L. 1519, No. 197, § 1, imd. effective.