Pirate Ship offers simple, discounted USPS shipping rates, with savings up to...

https://foxtrot-wiki.win/index.php/Shippo_for_WooCommerce:_Does_it_Handle_Multi-Carrier_Rate_Shopping%3F

Pirate Ship offers simple, discounted USPS shipping rates, with savings up to 87% off retail. It’s great if you want quick access to low-cost USPS labels and easy batch printing