Cardboard box, yes, something to think about. Few weeks back when I was investigating this issue, I found a web page where all the options shipping a bike were shown, with product pics and a short review of it, and it ended with cardboard box. I found promptly that it was not available in the shopping channels or from the maker.
While one could go to one of those places where they sell paper boxes for when people move house, I think some picture big boxes might fit the bill, but functionally it would probably not come even close to a paper box made for the purpose.
I found the webpage, feast with your eyes, think of your valet
I am sure the stated price of some $2k on that cardboard box is some mistake
https://www.bicycling.com/bikes-gear...-travel-cases/
I should pop into Fedex office near here to ask about shipping bike.
