Hi Capt, what is the value of the bass?
Our shipping method is a little too complicated for just anyone to do since it requires banding material and so on. I have mixed feelings about flight cases since the trucking industry managed to break two basses for us this Summer in flight cases. We strap and wrap bass boxes to a skid, standing up.
If it's a prized instrument, please find a way to drive it out yourself. Your nearby shops may have a box you can use if you're going to ship it. Insure it as if you expect it to get demolished. Be certain beyond a doubt that the person who will be receiving it does a complete, open-box inspection of the instrument before signing the delivery receipt, because once it's signed for, the shipper is off the hook. There is no such thing as a hidden damage claim.
My preferred shippers are FedEx Freight and UPS Freight, mainly because of fewer transfers from point A to B.
Good luck!