They sell them here too:
"Empty Wooden Cigar Box Assortment (10)"
http://www.cigarbid.com/auction/lot.cfm?lotID=395508
"Empty Cardboard Cigar Box Assortment (10)"
http://www.cigarbid.com/auction/lot.cfm?lotID=393871
I won a bid on the wooden boxes about two months ago (my winning bid was $7) for probably the same thing as what you're doing: have a bunch of empty boxes to dump all the five packs into then stuff into the cooler.
Since I had other winning bids that week, with the combined shipping, it was a very cheap way to go.
Ended up with a fair crossection of different box styles. A couple of sliding lid type boxes, some traditonal lightweght wood boxes, some laqured boxes, a couple of massive boxes, and even ended up with a CAO Black Man O' War box (I fail to see what the hype over the box is all about).