Pirate Ship is great if you want USPS labels up to 87% off and straightforward...

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

Pirate Ship is great if you want USPS labels up to 87% off and straightforward phone support. It’s perfect for sellers who ship mostly USPS. But if you need DHL Express or prefer email-only support, Shippo might be a better fit