815 ILCS 505/2J
No seller may include or cause to be included in any advertisement, price tag, display or other device used to describe the goods to be sold or to induce the purchase of those goods a statement that the goods may be purchased by weekly, monthly or other periodic payments unless that statement clearly sets forth the cash sale price of the goods in immediate conjunction with the amount of such periodic payment payable; the downpayment, if any; the number, amount and due dates or period of payments scheduled to repay the indebtedness if the credit is extended; and the rate of charge for credit expressed as an annual percentage rate.
A seller who complies with the federal Truth In Lending Act, amendments thereto, and any regulation issued or which may be issued thereunder, shall be deemed to be in compliance with the provisions of this Section.
A seller who violates this Section is guilty of an unlawful practice within the meaning of this Act.
815 ILCS 505/2J