Uline
National catalog of cartons, tape, mailers and paper. Same-day pickup at branches in most metros. Prices scale down aggressively past a case, and the whole catalog is priced online without an account.
Supplies primer
Boxes, tape, mailers and where each is cheapest
Every parcel a US seller ships is built out of five things: a box, tape, a mailer for smaller stuff, printed labels and something soft to fill the gaps. The cheapest source for each is different, and the wrong source turns a cheap label into a cheap label plus more packaging cost than the postage itself.
The five categories
Most operators pick one source for everything and pay for the convenience. The saving comes from splitting the list.
| Category | What you actually need | Where it costs least |
|---|---|---|
| Corrugated boxes | 32 ECT single-wall for parcels up to about 30 lb; 44 ECT double-wall for heavy or fragile | Uline for cartons over 30 a month, restaurant supply for one-offs, USPS Priority stock when the destination fits it |
| Tape | Clear polypropylene 2 in wide, 1.8 mil or heavier | Costco business center for a case of thirty-six rolls, dollar store for one |
| Mailers | Poly mailers for soft goods, bubble mailers for small hard goods, paper for eco-conscious brands | Amazon Business for poly, Uline for bubble, USPS free Priority padded flat-rate when the item fits |
| Printed labels | 4 x 6 in thermal for a Rollo or Zebra printer, or full-sheet adhesive paper for an inkjet | eBay's supply store for 4 x 6 thermal in bulk, office-supply chain for full sheets |
| Void fill | Kraft paper on a dispenser, air pillows for light items, foam sheets or corners for fragile | Whatever the local delivery driver leaves behind at your door for a month |
A dry-goods retailer running 20 packages a week is buying boxes and tape by the case. A person selling something from a closet twice a month should not.
The USPS free lane
The Postal Service will ship you Priority Mail packaging at no charge and drop it at your door. The catch is the label class it must go on.
The store at store.usps.com lists free Priority Mail and Priority Mail Express cartons, envelopes and stickers among its free shipping supplies, alongside labels sold in rolls of 250 or 1,000. Read on 2026-08-11. Priority Mail Express boxes are the fastest to arrive because USPS also ships the order Priority Mail Express. The rule the free lane runs on is the same rule that makes the cartons a trap for the wrong class: a box printed Priority Mail Flat Rate ships at the flat rate, not at your Ground Advantage rate, whether or not you ask.
Priority Mail Regional Rate boxes were retired in 2021, and the padded Priority envelope is one of the cheapest ways to ship a thick paperback or a small brass hardware order under one pound.
Wholesale sources near you
"Wholesale" here means twenty or more of the same carton, not a slightly cheaper single. Below the twenty-mark, retail sources usually win once shipping enters the total.
Costco Business Center
Cases of tape, kraft paper rolls, poly mailers and printer paper. Members can walk in and load a cart, and pricing on wide clear tape is often the best in the region.
Restaurant and janitorial supply
Every city has a wholesaler serving delis and cleaners. They carry stretch wrap, heavy tape, cardboard cake rounds for corner protection, and bulk kraft paper rolls at industrial prices, and they are always cash-and-carry.
Amazon Business
Fast when you need one case tomorrow. Not the cheapest per unit on tape or boxes, but the shipping is baked in, which changes the arithmetic if a case at Uline is triple digits to freight to your ZIP.
Local sign shops and print shops
Corrugated remnants from job runs are often sold cheap or given away. Ask for damaged cartons or overrun stock.
Facebook Marketplace and Craigslist
Businesses close and quit routinely. Cartons, mailers and unused rolls of thermal labels turn up under Free or under Business Equipment for a fraction of retail.
A packing kit that fits in a closet
For a household or a small side seller: one case each of 6 x 6 x 6 in, 10 x 10 x 10 in and 14 x 10 x 6 in single-wall cartons; a case of 2 in clear tape and one gun; a roll of poly bubble; a stack of poly mailers in one size that fits your bestseller; a roll of 4 x 6 thermal labels; and a Sharpie. That fits on a top shelf and covers eight parcels out of ten without a second trip.
For a store shipping every day: skip the mailers-as-catchall and buy carton sizes that match the top five items you sell. A carton one inch too big is a carton priced by dimensional weight, and dimensional weight sits above the actual weight on parcels above roughly 6 lb per cubic foot.
Where these figures come from
- USPS Postal Store, Free Shipping Supplies - listing of Priority Mail and Priority Mail Express packaging offered at no charge. Read 2026-08-11.
Common questions
Does USPS really give you boxes for free?
Yes, for Priority Mail and Priority Mail Express, ordered at store.usps.com and delivered to your door. The catch is that the box locks you into the class printed on it.
What is the cheapest tape?
A case of thirty-six rolls of 2 in clear polypropylene from a warehouse club, which lands around a dollar per roll and lasts a year for a small seller.
Where do people who ship every day buy boxes?
Uline for anything over a case, restaurant supply for a bag of miscellaneous, and the local sign shop for salvage when a job runs long.
What size box should I keep on hand?
Two or three sizes that match your top-selling items, not a wall of every size. An oversized box costs more in shipping than a right-sized one costs to buy.
Are Amazon boxes fine to reuse?
Yes, when the cardboard is sound and every old barcode and label is covered. USPS explicitly allows plain reused cartons for its own labels.