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Home > Guides > Are USPS Priority boxes free?
Yes. USPS gives away Priority Mail boxes, envelopes, and tubes free at post offices and online. The catch: a free Priority box may only travel as Priority Mail. Put a Ground label on one and the parcel can be surcharged or returned. This is US-only. LetterAgent labels are Canada-only Canada Post Xpresspost flat-rate (5 kg max): per-label quote, you approve the price, pay once via Stripe, label PDF provided.
| Free supply | What it is | Rule |
|---|---|---|
| Priority Mail flat-rate boxes (small, medium, large) | Sturdy boxes printed with "Priority Mail" | Must ship Priority Mail; flat-rate price regardless of weight (within limits) |
| Priority Mail padded flat-rate envelope | Bubble-padded envelope | Must ship Priority Mail |
| Priority Mail tube | Triangular tube for posters and documents | Must ship Priority Mail |
| Priority Mail Express boxes and envelopes | Express-branded packaging | Must ship Priority Mail Express, the fastest service |
The packaging is the advertising for the service, and USPS treats it that way. Every free box is printed with the service name, so a Priority box travelling on a Ground label is easy to spot at any sort facility. USPS can assess the missing Priority postage as a surcharge, hold the parcel until someone pays the difference, or return it to sender. None of that is theoretical; postal workers see misused packaging every day.
There is a second catch people miss: the free supplies are for mailing, not for storage or moving. USPS asks that you order only what you will actually use to ship, and ordering large quantities for non-mailing use violates the terms of the supply program. If you need boxes for a move, buy them.
Sometimes, yes, and that is exactly what the flat-rate boxes are for. If your item fits in a small flat-rate box and is heavy, the flat rate can beat paying by weight. But run the comparison honestly: a light item in a small town often costs less in your own box with weight-based postage than the flat-rate price in a free box. The free box saves you the cost of packaging, not the cost of postage.
Also note the branding cuts both ways. A Priority box announces its contents are worth the faster service, which most thieves ignore, but the bigger issue is practical: you cannot cover the Priority markings and reuse the box for a cheaper service. Once a Priority box, always a Priority shipment.
No. Canada Post does not hand out free packaging the way USPS does. Boxes, padded mailers, and tubes are sold at post offices and retail outlets, and Canada Post's prepaid flat-rate boxes are purchased products, not freebies. If you are used to the US system, budget for packaging when you ship from Canada.
This is one of the real US-vs-Canada shipping differences. Americans get free branded packaging and cheap flat-rate options; Canadians get a postal system with no free boxes and generally higher parcel rates. It is a big reason cross-border sellers on both sides plan their packaging and label buying separately.
Honestly: they don't, for this particular trick. LetterAgent sells Canada-only Canada Post Xpresspost shipping labels (5 kg max), so the USPS free-box strategy is outside what we cover. If you are shipping inside the US with a free Priority box, buy your postage from USPS or a US label retailer.
If you are shipping inside Canada, the flow is simple: ask your AI assistant for a label, get a per-label quote, approve the exact price, pay once through Stripe, and receive the label PDF to print and stick on your own box.
Ready to ship it? Get a shipping label with LetterAgent: describe it to your AI assistant, approve the exact quoted price, and get your label.
LetterAgent is a working name. Prices include print, postage, and our service fee. US prices in USD, Canadian prices in CAD (Canadian prices exclude applicable sales tax, added at checkout). Currently in private testing.
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