My packaging is fairly cheap, I read an article about 6 months ago from one of the top sellers in the type of product that I sell which said not to bother with fancy packaging, and I made the switch, no complains from my customers, in fact I've had quite a few return customers, which surprise me for hats.
I buy plastic shipping envelops about 11 cents
Since I know my postman likes to leave stuff on my doorstep with out outer plastic regardless of weather, I always, put my hats in a store brand ziplock style bag inside, maybe another 10 cents. I actually store my stock this way till ready to ship.
Lastly, I but my shipping labels off of amazon, again maybe 10 cents
So I'm guessing a total of about 30 cents