Having ran a couple mailorder hobbies, I'm rather impressed that they care about their product that much. They could have crammed it into a golf club box, or something like that, but why disturb their work? The price on oversized box shipping, regardless of weight, has gone nuts. I used to ship backpacks (the expedition types) for around $20-25, and those are now $100. Good luck finding large boxes that are just the right size. I used to raid the grocery store recycling dumpster.
A very long time ago, at a job and manufacturing fair at a community college, a Better Business Bureau representative told us that if you wanted to start a business that was nearly a shoo-in for success, they recommended starting a shipping box factory. Every region needs a corrugated cardboard box maker. And this was pre-Amazon/pre-internet. Oh, how so-very right they were. The other prophetic entrepreneurial advice I got was "get into storage." And this was a decade before all these storage places popped up everywhere. I thought the guy was crazy, but that guy laughed last. I digress.