Uniform Commercial Code (UCC): Primary framework for commercial transactions in the US, particularly Article 2 (Sales) and Article 9 (Secured Transactions), governing sales and security interests in personal property.

Federal Trade Commission (FTC) Regulations: Federal regulations governing consumer protection, including mandatory disclosure requirements and cooling-off period rules for certain transactions.

Truth in Lending Act (TILA): Federal law requiring disclosure of credit terms and providing consumer protection provisions in credit transactions.

State-Specific Laws: Individual state variations of the UCC, state consumer protection laws, disclosure requirements, and usury laws regarding interest rates.

Magnuson-Moss Warranty Act: Federal law governing warranties on consumer products, specifying requirements for written warranties and consumer remedies.

Fair Credit Reporting Act: Federal law regulating the collection, dissemination, and use of consumer credit information, relevant when credit checks are part of the transaction.

Equal Credit Opportunity Act: Federal law prohibiting discrimination in credit transactions based on race, color, religion, national origin, sex, marital status, age, or public assistance program participation.

Consumer Credit Protection Act: Federal law providing a comprehensive framework for consumer credit protection, including regulations on credit terms and practices.

State Contract Law: Basic contract formation requirements and statute of frauds provisions specific to each state, governing the formal requirements for valid contracts.