"Shipping bags" covers plain poly mailers, bubble-lined mailers, paper mailers and a handful of branded envelopes carriers give away, and the cheapest one to buy depends more on size and material than on where you shop. Five real sellers, each read on its own product page on 2026-08-30, are below with a per-bag price rather than a pack price.
Every figure below is divided down to one mailer so a pack of 10 and a case of 1,000 sit on the same scale.
The everyday white or colored bag most soft-goods sellers use. Size and gauge move the price more than the retailer does.
| Seller and item | Size | Pack / case | Price per bag |
|---|---|---|---|
| Staples, Poly Pak America Peel & Seal Poly Mailers | 7.5 x 10.5 in | 100-pack, 11.79 USD | 0.118 USD |
| Amazon, à la mode Mailers poly mailers | 10 x 13 in | 100-pack, 19.99 USD | 0.200 USD |
| Uline S-21878, tear-proof, 20+ cases | 10 x 13 in | Case of 1,000, 176 USD at 20+ cases | 0.176 USD |
| Uline S-21878, tear-proof, single case | 10 x 13 in | Case of 1,000, 194 USD for 1 case | 0.194 USD |
Staples' smaller, lighter-duty bag beats every Uline tier here, including Uline's own 20-case discount price, because it is a smaller bag on a different film gauge — a reminder that a wholesaler's case price is not automatically the floor. Amazon's 100-pack sits between the two, close to Uline's single-case rate for the same 10 x 13 in footprint.
Cushioning roughly doubles the per-bag price against a plain poly mailer of similar size. Size matters less here than where you buy: a retail pack of small mailers came in under a wholesale case of larger ones on the day these were read.
| Seller and item | Size | Pack / case | Price per bag |
|---|---|---|---|
| Walmart, Pen+Gear #0 Kraft Bubble Mailer | 6 x 9 in | 15-pack, 5.92 USD | 0.39 USD |
| Uline S-7547 #4, 10+ cases | 9.5 x 14.5 in | Case of 100, 42 USD at 10+ cases | 0.420 USD |
| Uline S-7547 #4, single case | 9.5 x 14.5 in | Case of 100, 48 USD for 1 case | 0.480 USD |
Uline's own case discount on the same #4 mailer runs from 48 cents down to 42 cents between 1 and 10 cases. Walmart's #0 undercuts even that best tier by about three cents a bag, on a mailer 3.5 in narrower and 5.5 in shorter — whether the extra room is worth three cents depends entirely on what is going in the bag.
USPS is the outlier on this page: it does not sell a plain shipping bag at any price, but it gives away a branded one.
| Item | Size | Pack | Price |
|---|---|---|---|
| Priority Mail® MILI-PAC Envelope | 15 x 11-5/8 in | 10-pack | 0.00 USD |
That envelope, water-resistant poly with a self-seal strip, ships on Priority Mail postage and nothing else — put a Ground Advantage label on it and USPS bills the parcel as though it went Priority Mail regardless. Our USPS poly mailer explainer covers that trade in full; the short version is that the zero price is real, but it is not a substitute for one of the paid plain mailers above on a cheaper class of service.
Uline's own tiers show the real shape of a case discount: its plain poly mailer fell from 19.4 to 17.6 cents a bag between a single case and 20-plus cases, about 9%. Its bubble mailer fell from 48 to 42 cents between 1 and 10 cases, about 12.5%. Neither is a dramatic curve.
A smaller or lighter-gauge bag from a different seller can undercut a bulk case of a bigger or heavier one outright, which is exactly what Staples' 100-pack did to Uline's case pricing above. Compare the spec, not the seller's reputation for bulk pricing.
A seller moving fewer than a couple hundred parcels a month rarely clears even the smallest wholesale case count before the mailers age or the business's needs shift; a Staples or Amazon retail pack in the right spec is often the better buy at that volume, case discount or not.
Each figure above is a snapshot from the named seller's own listing on 2026-08-30; mailer pricing shifts with material costs and promotions more often than carton pricing does.
Packaging wholesalers like Uline sell poly and bubble mailers by the case, Amazon and Walmart sell retail packs of the same materials, Staples sells small office-style packs, and USPS gives away its own branded poly envelope tied to Priority Mail. Checked live 2026-08-30, per-mailer prices across these five ranged from about 12 cents to 48 cents depending on size and cushioning.
Not always the biggest case. On 2026-08-30, a 100-pack of 7.5 x 10.5 in poly mailers at Staples ran 11.79 USD, or 11.8 cents each, cheaper per bag than Uline's 10 x 13 in tear-proof mailer even at its 20-case price of 17.6 cents each. The gap is size and material, not volume: check the per-unit price for the exact spec you need before assuming the bigger case wins.
USPS gives away its own Priority Mail poly envelope, checked at 0.00 USD in packs of 10 on 2026-08-30, but that packaging is tied to Priority Mail service and is not a substitute for a plain mailer on a cheaper class. Our USPS poly mailer guide covers that trade-off in full.
Roughly two to two and a half times, at the same wholesaler. Uline's plain 10 x 13 in poly mailer ran 17.6 to 19.4 cents each depending on case count on 2026-08-30, while its bubble-lined #4 mailer at 9.5 x 14.5 in ran 42 to 48 cents each the same day.
The discount for buying more of the same product is real but modest: Uline's own poly mailer dropped only from 19.4 cents at a single case of 1,000 to 17.6 cents at 20-plus cases, about a 9% spread, checked 2026-08-30. A different size or material from a different seller can beat both prices regardless of case count, so compare the specific spec, not just the quantity.