Yes, since I didn't know the measurements, I left it entirely off, and I guess
the default mode is 1 inch cube. I still think FedEx is cheaper than UPS or
other freight carriers.
I'm not sure if it's still the case, but when I worked in logistics they were usually one of the more expensive way to ship freight, and unless it's a small piece of furniture you'd need to go to a separate FedEx form for a freight quote and a skid with them would probably be over $600.
I would have looked elsewhere first (the kind of site Rock recommended would be my first bet). But the parcel couriers have been doing a lot to push into logistics services since I worked with them so this may have changed, and they may be better at this kind of shipping now.