Pirate Ship is great if you want deep USPS discounts—up to 87% off—and...

https://bizzmarkblog.com/pirate-ship-vs-shippo-for-beginners-which-is-less-confusing/

Pirate Ship is great if you want deep USPS discounts—up to 87% off—and straightforward, no-fee shipping. Just note, their support is email-only, and they don’t offer DHL Express. If you need more carrier options or faster help, Shippo might be better