The Cheapest Way to Ship in 2021

Read about the cheapest way the ship in 2021, including FAQs, potential discounts, and information about the most popular shipping companies.

Updated on June 17th, 2021

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If you have an online business or work in a retail industry where shipping is necessary, you may be looking for a cost-effective way to ship your items. While most courier services have standard rates, we have outlined any unexpected expenses you may incur, and how to avoid them.

The most popular shipping services are USPS, UPS, and FedEx. Read on to learn about the cheapest way to ship in 2021.

Things to Consider When Choosing a Shipping Method:

  1. Some courier services offer discounts for frequent shipments or shipments with many packages.
  2. Irregularly-shaped boxes will be priced according to their size instead of their weight, so it would be cheaper to use a standard box with a flat rate.
  3. Dropshipping is an excellent way to avoid storing excess inventory by using a supplier's shipping facilities to deliver directly to your customers.

Tip for keeping shipping costs low:

If it makes more logistical sense to use a courier company for shipping, you'll want to keep weight in mind. Shipping costs are usually calculated according to the size and weight of your package.

Try to use the standard boxes from the shipping service of your choice, as an irregularly-sized box will be charged for its dimensional weight.

Cheapest Shipping Service By Weight:


Shipping Service

Under 1lbs.

USPS First Class Mail

Under 10lbs.

USPS Priority Mail

Over 15lbs.

FedEx Ground


USPS New User Discounts:

  • 40% off Priority Mail.
  • 18% off First Class Mail Package.
  • 13% off Priority Mail Express.
  • 5% off International First Class, Priority Mail, and Priority Mail Express.
  • 40% off USPS Package Insurance Rate.

USPS Priority Mail Flat Rate Pricing:

Package Type



Flat Rate Envelope

12-1/2" x 9-1/2" or smaller


Legal Flat Rate Envelope

15" x 9-1/2"


Padded Flat Rate Envelope

12-1/2" x 9-1/2"


Small Flat Rate Box

8-5/8" x 5-3/8" x 1-5/8" Inside; 8-11/16" x 5-7/16" x 1-3/4" Outside


Medium Flat Rate Box

11" x 8-1/2" x 5-1/2" Inside; 11-1/4" x 8-3/4" x 6" Outside


Medium Flat Rate Box

13-5/8" x 11-7/8" x 3-3/8" Inside; 14" x 12" x 3-1/2" Outside


Large Flat Rate Box

12" x 12" x 5-1/2" Inside; 12-1/4" x 12-1/4" x 6" Outside


Large Flat Rate Box

23-11/16" x 11-3/4" x 3" Inside; 24-1/16" x 11-7/8" x 3-1/8" Outside


APO/FPO/DPO Flat Rate Box

12" x 12" x 5-1/2" Inside; 12-1/4" x 12-1/4" x 6" Outside



UPS package sizes are classified according to cubic inches. A cubic inch is calculated with the following formula:

Length (L) x Width (W) x Height (H) = Cubic Inches

UPS Package Sizes:

Size Name

Cubic Inches


Extra Small












Extra Large




FedEx provides pricing according to location, size, and delivery time. The following prices reflect shipments made within 0–150 miles from origin to destination with the Express Saver shipping option. This is the cheapest option and delivers your package in 3 days.

FedEx Domestic OneRate Pricing:

Package Type


FedEx Envelope


FedEx Pak


FedEx Small Box


FedEx Medium Box


FedEx Large Box


FedEx Extra Large Box


FedEx Tube


FedEx New User Discounts:

  • 16% off on select FedEx Express services.
  • 8% discounts on select FedEx Ground and Home Delivery services.
  • Up to 60% discounts on FedEx Freight services.

Dimensional Weight:

USPS, FedEx, and UPS all charge for 'dimensional weight'. This applies to packages that are irregular sizes or very large.

Each company has a different formula for calculating dimensional weight, outlined below.

Dimensional Weight Formulae:









Shipping insurance:

If you are shipping valuable items or bulk items for customers, shipping insurance is invaluable to protect your business against damaged or lost packages.

Shipping Insurance Pricing:



USPS Priority Mail







Dropshipping is a method of shipping that makes use of a manufacturer or supplier's facilities. If you are ordering your stock from a supplier who has a warehouse and shipping operations, you can schedule individual orders to be sent directly to your customers instead of having stock sent to you. This saves space and money that would have been spent on additional shipping.

Amazon Seller Central is one example of a company that offers dropshipping services. Amazon will house merchandise in their warehouse, and ship from their warehouse directly to your customers.


What is the cheapest way to ship a package with USPS?

The cheapest way to ship a package with USPS is by using flat rate boxes if your package weighs more than 2lbs. Irregularly-shaped boxes will be charged more heavily than standard sizes, regardless of weight.

What is the cheapest way to ship clothes?

Depending on the weight of the package, USPS is regarded as cheaper when your package is under 2lbs.

If your package is heavier than this, it would be cheaper to use a flat rate box from UPS or FedEx.

Does USPS charge by weight or size?

USPS charges for dimensional weight when a package has a large or irregularly-sized box. Otherwise, USPS charges by size when you ship with their flat-rate packages.

Can you ship a shirt in an envelope?

Yes, you can ship a shirt in an envelope if the envelope seals completely.

How does flat-rate shipping work?

Flat-rate shipping works by having the courier service sell branded boxes in standard sizes (small, medium, and large) and charging a set fee for shipping, regardless of weight.

Is it cheaper to use a flat-rate box or your own box?

If your package weighs less than 2lbs, it would be cheaper to ship it in your own box (provided that it is a regular size). If your package weighs more than 2lbs, it would be best to use a flat-rate box to ensure that no additional fees are billed because of weight.

Is FedEx faster than UPS?

FedEx Express Saver shipping takes 3 business days to deliver, while UPS estimates that their UPS Ground shipping will deliver within 5 days.

How can I lower my shipping costs?

  • Look for discounts offered to new users.
  • Compare quotes from several carriers.
  • Use flat rate boxes where possible to ensure that there are no additional fees.
  • Make use of online shipping services to receive discounts that may be offered online.

Can I use my own box for flat-rate shipping?

No, you must use the flat-rate box supplied by the courier service.

How big is a large flat-rate box?

The dimensions of large flat-rate boxes are 12 x 12 x 5.75 inches.

Can I ship my own box through USPS?

Yes, but the box must have official USPS labels on it when shipping.

What are the sizes of flat-rate boxes?

The dimensions of flat-rate boxes are outlined on EasyPost.