What is NOT a method for paying postage with USPS?

The method that is not a valid way to pay postage with USPS is the use of coins. The Postal Service has established specific forms of payment for postage, which include stamps, prepaid labels, and postage meters.

Stamps are a traditional and widely recognized method of affixing postage to mail. Prepaid labels allow customers to pay for postage in advance and are commonly used for shipping packages. Postage meters provide a convenient way to pay for mail services directly and can often be used for bulk mailing or for businesses that send out large volumes of mail.

Coins, however, are not accepted as a method of paying for postage in any official capacity with the USPS. This is largely due to operational efficiency, transaction simplicity, and security reasons. By requiring standardized forms of payment, the USPS can streamline its processing and reduce potential issues that might arise from accepting cash in the form of coins.