Through Amazon Buy Shipping
For Amazon orders. Labels on protected services don't count against your on-time delivery rate if they arrive late. In PolyBag, these quotes are marked “via Amazon.”
Your own carrier accounts vs. aggregator shipping rates
An aggregator rate is postage priced through a shipping platform's carrier agreement. A direct-account rate belongs to your business. Either can be useful—and opening an account is not the same as qualifying for a custom negotiated agreement.
When an aggregator is genuinely the better choice
Aggregator rates are convenient when you want one login, do not want to manage carrier relationships, or can already buy a strong rate through Amazon, Shopify, ShipStation, Shippo, or Pirate Ship. A direct account is not automatically cheaper for every package.
PolyBag supports Amazon Buy Shipping for Amazon orders and Shopify Shipping for Shopify orders. Amazon exposes quotes that PolyBag can compare; Shopify selects its own best available option because its API does not expose those quotes for comparison.
What a direct account gives you at any volume
- Rates and billing attached to your own business rather than a reseller's master account
- A direct carrier relationship for pickups, claims, invoices, and account history
- Standard account discounts without waiting to qualify for a custom contract
- A foundation for negotiating deeper rates once your volume and shipment profile justify it
USPS says its online business tools offer lower commercial rates. FedEx says its free accounts include built-in discounts with no minimum volume, and UPS says its shipping accounts are free to open.
Two ways to use your accounts with Amazon orders
Amazon lets you link your own carrier accounts to Buy Shipping in Seller Central (Shipping Settings → Carrier Accounts). Buy Shipping then quotes your rates, the carrier bills you directly, and eligible labels keep Amazon's on-time delivery protection. PolyBag can use your accounts either way.
Direct to the carrier
For orders from any channel, including Shopify. Amazon orders shipped this way don't get Buy Shipping's protection, so late deliveries count against your on-time delivery rate.
You can use both. If a service is available both ways, PolyBag lists both quotes. Shipping methods can require protected offers for selected Amazon order types, such as Prime, and use direct quotes for everything else.
What changes at higher volume
Higher volume can make a custom agreement worthwhile. A provided USPS Mid-Market rate sheet lists a commitment of 8,750 Ground Advantage packages per quarter—35,000 per year—for its first NSA tier. That is a negotiated tier above ordinary commercial pricing, not a minimum for opening an account.
FedEx and UPS conversations commonly begin around $25,000–$50,000 in annual parcel spend, but treat that as a planning range rather than a published eligibility rule. Package mix, zones, dimensions, services, surcharges, and competitive bids all affect the offer. Ask a carrier representative to model your own data.
How to open the accounts
USPS
Create a free USPS.com business account using your business email, company information, address, and contact details. USPS verifies the email and business address during registration.
Create a USPS business accountFedEx
Open a free business account online. FedEx asks for billing information and issues a nine-digit account number when setup is complete.
Open a FedEx accountUPS
Create or sign in to a UPS profile, then add a free shipping account. UPS requires a payment method because optional services such as recurring pickups may carry charges.
Open a UPS accountWhere PolyBag fits
PolyBag's main job is to stop packing errors before a label prints. You can start with supported Amazon or Shopify postage, use Amazon Shipping after completing its separate signup, or connect direct carrier accounts. As your rates change, the scan-and-weigh packing workflow does not.
See shipping software for Amazon and Shopify sellers