Use cardboard, cut many pieces and tape them 
together firmly, maybe for 2-3 layers, to avoid 
bending.

Then, take paper grocery bags, label-sides in, 
and use them sort of as a wrapping paper.  That's 
what I do usually for my overseas packages.  Or, 
you could actually just use wrapping paper, white 
side out if you wanted.

Hope this helps,
Kristina