(I hope this get's sticky'd)
I presently have two basses to ship, and no boxes.
So I trot on over to my two local music stores to ask if
I can have a few from recent shipments.
One has NO boxes (no recent shipments) but is very nice
about it.
The other wants to charge me $20/box for used
boxes that come to them.

(And I am a customer
of both stores I might add...)
Then one of the buyers gives me a GREAT suggestion that
immediately pans out --
bicycle boxes!
I trot on over to my local bike shop, and next to the dumpster
are like 30 of them, so I help myself and am on my way!
Just wanted to pass this on to the rest of you who may need
a box on short notice.