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
The US Postal Service officially accepts the following credit cards: MasterCard American Express Digital Wallets (Apple Pay, Google Pay) Payment Acceptance Policies - About USPS Home
Major retailers like Walmart, CVS, Walgreens, and Rite Aid typically accept credit cards for stamp purchases.
You can use a credit card at full-service retail counters and USPS self-service kiosks.
You can use a credit card on the official USPS Postal Store or via third-party sites like Amazon and Stamps.com . Accepted Payment Methods at USPS
Most large supermarkets (e.g., Publix, Kroger) sell stamps at the checkout or customer service desk and accept credit cards.