You will find a number of third party services that will offer you discounted USPS shipping including stamps.com, shippingeasy.com, shipstation.com, etc. Note that many of these services are getting bought up by stamps.com, which actually may end up benefiting everyone as they will have more leverage to get better rates from USPS.

You'll also be able to get a discount when you use some shopping carts like Shopify.com.

Bottom line - shop around and see which one will give you the best rates - the higher the volume, the better the rate!

Depending on your shipping volume, you'll likely find better rates through a USPS consolidator, like DHL.

A consolidator works in conjunction with USPS. They typically pick up mail at your location, deliver it to their nearest shipping hub and then deliver each piece to the USPS location closest to the shipping destination. The mail is passed off to USPS and USPS takes it from there, delivering to the customer.

UPS and Fedex (I believe) also offer similar services.

You can find commercial rates for USPS shipping on their website. Here's how:

Go to the USPS website (www.usps.com) and click on the "Business" tab at the top of the page.

Under "Shipping", click on "Calculate a Price".

Enter the weight and dimensions of your package, as well as the destination zip code.

Select "Commercial Base Pricing" to view the discounted rates available to businesses.

Choose the shipping service you want to use, such as Priority Mail or First-Class Package Service, and the type of delivery (e.g. one-day, two-day, or standard).

The website will then display the shipping cost for your package based on the options you selected.

Keep in mind that USPS rates may vary based on the size and weight of your packages, as well as the shipping speed and delivery location. You may also be able to get additional discounts on USPS shipping by using an online shipping platform or by signing up for a USPS business account.