USPS now has a new service....Ground Advantage, along with their Priority Mail option. It is cheaper, much cheaper to some places, than Priority. And, in checking the 14 boxes (under 30" of course) I shipped Thurs./Fri., I'm finding all delivered Sat. or out for delivery today!!
To FL, NY, CA, WA, etc..
I did not check with Pirate Ship, but don't think they can beat the prices on ShipStation, as low as they were.
In almost all cases, pricing was $1-2 lower than Priority.