Pirate Ship offers USPS discounts up to 87%, making it a great choice if you...

https://technivorz.com/does-shippo-really-offer-strong-ups-rates-compared-to-other-tools/

Pirate Ship offers USPS discounts up to 87%, making it a great choice if you mostly ship domestically with USPS. Their easy-to-use interface is a plus, but support is email-only, which can slow things down