Thanks for sharing that $1 cost. It's for exactly this reason that we prefer to use many USPS Priority Mail flat rate mailers/boxes because they are free. In one case requiring a special cardboard tube, we looked into getting our own tubes but the cost was close to $3 unless you wanted to buy 1000 units. So we stuck with USPS "triangular tubes" which are included in the price of a $14 flat rate postage anywhere in the U.S.