Where is the cheapest place to buy shipping boxes?
A packaging supplier, if you can take the minimum bundle. On 2026-07-28 Uline listed a 12 by 10 by 6 inch 200 lb test carton at $0.94 per box in bundles of 25, and Staples listed the same footprint at $1.26 per box in bundles of 25. Buying one box at a time costs more everywhere.
Can I buy just one shipping box?
Yes, from moving and home improvement retailers. On 2026-07-28 U-Haul listed its small moving box at $1.77 for one and $34.75 for a bundle of 25, and Home Depot listed an 18 by 18 by 16 inch moving box at $1.34 each. The premium for a single is real but small.
Is it worth buying boxes when USPS gives them away?
Only when you want the postage that comes with them. USPS lists Priority Mail and Priority Mail Express packaging at $0.00 in its Postal Store, and usps.com states that if you use a Priority Mail box, you have to pay for Priority Mail service. A purchased carton leaves the service choice open.
How much does the box matter next to the postage?
Very little. A 12 by 10 by 6 inch carton holding 5 lb quoted $13.52 from Newark, NJ 07102 to Atlanta, GA 30303 on 2026-07-28, about fourteen times what the cardboard cost. Choosing the right size saves far more than choosing the cheap cardboard.