When I wanted to post a parcel with my paintings I ran into the problem of not being able to source a standard size box for them. I was told that the carrier had stopped selling the size I wanted.
However, they did recommend to enquire at a DIY or a super market. I tried the latter and was given a carton for free albeit the wrong size. So it will need a bit of trimming and taping.
Have you ever come across a similar obstacle?