Paper, however, is certainly available in abundant quantities. You don't even have to use paper! Magazines, plastic bags, etc are all possible candidates.
And since it's made from paper, it's customizable with markers, or create it with coloured paper to have a colourful box.
Magazines with glossy paper work really well as containers for bones and the ilk.The glossy paper stops the oil from 'leaking' and the box allows easy disposal.
Difficulty? So easy a toddler could probably do it. Assuming his/her attention span is long enough.
Also, no cutting required, making it very safe. Well, the worst is that you might choke while swallowing it, but if you swallow it in the first place...
Flexibility? Whatever thing a box can do, it can do. Cause it's a box. Add a lid, and have a box, and make it out of wrapping paper to have a quick gift box.
Make some out of wrapping paper and use it to decorate the house as 'present' boxes, except empty ones.
Step 1: Step One
Staples are not necessary, but I advise it for securing the paper later.
Note : Creasing the paper when folding it for the first time is recommended, to help with the crispness to aid step 3.