I use that size box from Uline, too.
I've been struggling a bit trying to find a way to package headbands in a way that's pleasing to the eye but also keeps them safe. I use a lot of feathers in my creations, and I always worry about the delicate feathers being smooshed. Initially, I wrapped them carefully in a lovely tissue paper and then wrapped the outside with pretty ribbon and a tag, then put that in a cello bag and placed it inside the mailing box. But I've found that the tissue does cause some "smooshing" of the feathers. Without the cello bag and tissue, though, I worry about water damage if the mailman leaves the package on the customer's porch during inclement weather. So...yeah...I'm really struggling with how to mail and package these too! Would love to hear some more ideas.