From:
https://www.expertlaw.com/library/consumer-protection/it-legal-refuse-cash-paymentIt is a widely held belief that, in the United States, a business must accept cash payments from a consumer. Some people take the argument a step further, arguing that if a business refuses to accept cash from a customer, the business loses its ability to charge the customer. Neither belief is true.
Federal Law and Cash Payment
Paper currency in the United States is printed with the provision that it is "legal tender for all debts, public and private", language that flows from the provisions of a federal law, 31 U.S.C. Sec. 5103,
United States coins and currency (including Federal reserve notes and circulating notes of Federal reserve banks and national banks) are legal tender for all debts, public charges, taxes, and dues. Foreign gold or silver coins are not legal tender for debts.
The principal purpose of that statute is to ensure the nationwide acceptance of U.S. currency, consistent with constitutional language that reserves to Congress the power to create a uniform currency that holds the same value throughout the United States. While the statute provides that U.S. money is legal tender that may be accepted for the payment of debts, it does not require acceptance of cash payments, nor does it provide that restrictions cannot be imposed upon the acceptance of cash.