Cheap firearms shipping cartons source

There have been several posts over the years seeking a source of inexpensive shipping cartons for long arms.

I buy all my shipping cartons from Uline and while I don't deal in firearms, I noticed they have their 6x6x36 and 6x6x48 boxes on sale at the moment. Granted these are not large enough to ship a scoped rifle or or one inside a hard case, but for those who are shipping inexpensive single shots or the like, the price is hard to beat if one is buying boxes.

http://www.uline.com/BoxListing1.asp