What happened to your own box, anyway?
I always keep my boxes, especially for computers. You're going to have to sell every computer and upgrade it sometime. Having the original box will not only make shipping easier, but it helps boost resale value too.
If you look on eBay, people are selling their empty 27" and 21.5" iMac boxes (both 2012 and pre-2012 variants). However, they are charging $50 to $70 for them and people are actually buying them. Ridiculous how even an Apple box is valuable. 😱