The Postal Store is the official online store of the United States Postal Service, where you can buy stamps, mailing supplies, collectibles, and more. Shop by category,Shop for stamps, supplies, cards, envelopes, collectors' items and more at The Postal Store @ USPS.com. Browse over 700 results of products from various categories and brands, Premium Shipping Supplies. Simplify your mailing and shipping with. supplies like scales, ReadyPost®. packaging, and more. Shop Now. Shipping Supplies.