While the boxes themselves are free from USPS, some third-party services sell "kits" or bundles that include extra supplies like tape or labels for convenience.
You can get for free directly from the United States Postal Service . Because these boxes are intended to encourage the use of Priority Mail services, the Postal Service provides the physical packaging at no cost—you only pay the flat rate shipping fee when you actually mail them. Where to Get Them 📦 Local Post Offices where can you buy usps flat rate boxes
Find the for your specific package weight. While the boxes themselves are free from USPS,
💡 If your local post office is out of a specific size, try the Self-Service Kiosk area; sometimes they keep a small stash there for after-hours customers. If you’d like, I can: Where to Get Them 📦 Local Post Offices
Sometimes sells lots of boxes or pre-packed "shipping kits," though it's often more expensive than getting them directly from the source.