(a) Any waiver of the buyer of this chapter shall be deemed contrary to public policy and shall be unenforceable and void.
(b) If this chapter or the application thereof to any person or circumstances is held unconstitutional, the remainder of the chapter and the application of such provision to other persons or circumstances shall not be affected thereby.
(c) Except as provided in § 4315 of this title, this chapter shall not apply to any retail installment sale which is made for a cash sale price of $75 or less, where no title, lien or other security interest is retained or taken by the seller. This section shall not apply to sales made pursuant to the provisions of §§ 4334-4343 of this title.