Pirate Ship offers USPS shipping up to 87% off with easy label printing and no...

https://mike-wiki.win/index.php/Shippo_vs_Pirate_Ship:_Which_One_Has_Better_Integrations_for_Marketplaces%3F

Pirate Ship offers USPS shipping up to 87% off with easy label printing and no monthly fees—great if you mainly ship domestic. Just know their customer support is email-only, which might slow things down