Poshmark's fixed label, Mercari and eBay labels, Whatnot's per-show labels, and the orders where Pirate Ship's free USPS and UPS rates save money.
Updated October 9, 2026
Before you start
Poshmark's fixed label, Mercari and eBay labels, Whatnot's per-show labels, and the orders where Pirate Ship's free USPS and UPS rates save money.
Most US marketplaces sell you a shipping label inside the app. Pirate Ship is a free label site that passes on USPS and UPS commercial rates with no monthly fee. Each wins on different orders.
Rates and rules change, so check the label price on the screen before you print. Every price below is a typical band, not a quote.
Kit for this
The products this guide uses, with typical US prices.
MUNBYN thermal label printer
It takes the standard 4 × 6 inch labels that eBay, Poshmark, Mercari and Whatnot all generate, and generic labels work, so the running cost stays low.
Typical price$60 to $100
See on Amazon
4 × 6 in thermal labels, 500 fanfold
Fanfold stacks feed flat behind the printer and hold more labels than a roll. 4 × 6 in matches the label size USPS, UPS and the marketplaces print.
Typical price$8 to $16
See on Amazon500 g precision pocket scale
Card orders often sit a fraction of an ounce from a postage price break. A precise small scale tells you whether a mailer stays in the cheaper weight step.
Typical price$8 to $15
See on AmazonThe guide
Each step in the order you'll need it.
Poshmark: one label, paid by the buyer
Poshmark emails a prepaid label for every sale and the buyer pays for it at checkout. You do not pick the carrier or the service, and the label covers packages up to a set weight.
That makes off-platform labels pointless for most Poshmark orders. Use the Poshmark label and spend the time on the next listing.
Mercari, eBay and Etsy labels
Mercari, eBay and Etsy each sell discounted labels inside the order screen, with USPS and usually UPS or FedEx. The cost comes out of your payout or the buyer pays at checkout, depending on how you listed it.
In-app labels keep tracking linked to the order, which helps when a buyer opens a case. That protection is worth a few cents on most sales.
Whatnot: labels per show
Whatnot generates labels after a show, grouping each buyer's wins into one package, and the buyer pays shipping. You print them in a batch from the seller app or desktop.
Off-platform labels make no sense here either. A thermal printer that takes 4 × 6 in labels cuts a 40-order show to a few minutes of printing.
Where Pirate Ship pays off
Pirate Ship helps on sales where you control the label: Facebook Marketplace shipped orders you arrange yourself, your own website, local buyers who pay by app, and eBay listings where its rate beats eBay's.
It also suits heavy or bulky items. Comparing USPS and UPS on one screen often finds a cheaper option for a 6 lb box than the platform shows.
Weighing and measuring right
Off-platform labels price on the weight and size you type in. Guess low and USPS can charge the difference back to your account later.
A small digital scale and a tape measure fix that. Weigh the packed box, not the item, and round up.
Kit for this step
Keeping the paper trail
A label bought off-platform still needs the tracking number in the order. Paste it into the marketplace the same day so the sale shows as shipped and your seller protection stays in place.
Save label receipts with your other costs. On Schedule C, shipping you pay is a business expense.
Checklist
Run through it before each one goes out.
- 1Use Poshmark and Whatnot labels for those orders
- 2Compare eBay's label rate with Pirate Ship on heavy items
- 3Weigh every packed box and round up
- 4Measure boxes over a cubic foot
- 5Paste off-platform tracking into the order the same day
- 6Keep every label receipt for your records
Setups
Complete kits for one kind of seller, costed and laid out.
Questions
Straight answers to what sellers ask about this.
Is Pirate Ship free?
Pirate Ship says it charges no monthly fee and no markup. You pay only the postage on each label.
Can I use Pirate Ship for Poshmark sales?
Poshmark sends its own prepaid label that the buyer already paid for, so there is no reason to buy another.
Are eBay labels cheaper than Pirate Ship?
Sometimes. Both use commercial rates. Compare the two on the order screen for anything over a pound or two.
Which carriers does Pirate Ship offer?
USPS and UPS, from US addresses.
Do I need a thermal printer?
No, a home printer and tape work. A thermal printer that takes 4 × 6 in labels saves time once you ship several orders a day.
What if I enter the wrong weight?
USPS can bill the shortfall later as an adjustment. Weigh the packed box and round up.