Maryland Code, Commercial Law § 12-610

(1) An amount computed using the following annual simple interest rates of finance charge:

(2) A minimum charge of $10 or, if the date of the last installment is eight months or less after the effective date of the installment sale agreement, $8.

(3) Notwithstanding the provisions of subsection (1) of this section, a seller may charge a finance charge at a rate not in excess of 24 percent per annum simple interest on the outstanding balance under an installment sale agreement made on or after July 1, 1982.