You can use a credit card at full-service retail counters and USPS self-service kiosks.
Yes, you can absolutely buy stamps with a credit card at most locations, including the post office, major retail stores, and online . Where to Buy Stamps with a Credit Card can i buy stamps with a credit card
Most large supermarkets (e.g., Publix, Kroger) sell stamps at the checkout or customer service desk and accept credit cards. You can use a credit card at full-service
Major retailers like Walmart, CVS, Walgreens, and Rite Aid typically accept credit cards for stamp purchases. including the post office