You can also check the USPS Parcel Post rate on-line (including over-sized items).
I gave up on sending large items by Greyhound Bus Lines because the local station's shipping manager is a jerk (he will often not give shipping estimates and he will not honor estimates he has given). After two bad experiences, I do not even try - competition is a wonderful thing: Fed Ex, UPS, and USPS (DHL was competitive but no longer available).
If you register for Fed Ex on-line and pay on-line, you now get a discount.
