regular price
(y) As used in this section and section 1666f of this title , the term “regular price” means the tag or posted price charged for the property or service if a single price is tagged or posted, or the price charged for the property or service when payment is made by use of an open-end credit plan or a credit card if either (1) no price is tagged or posted, or (2) two prices are tagged or posted, one of which is charged when payment is made by use of an open-end credit plan or a credit card and the other when payment is made by use of cash, check, or similar means. For purposes of this definition, payment by check, draft, or other negotiable instrument which may result in the debiting of an open-end credit plan or a credit cardholder’s open-end account shall not be considered payment made by use of the plan or the account.