[arewhyehen]

Pizza boxes, preferably clean ones with extra packing top & bottom.
Try a post office or ups store, even some dollar stores sell cartons.
If he's in Montreal I have a bunch in the basement.

Oh god no. Please not a pizza box.

Go to your local record shop and they will probably have some. Where are they located? I have a bunch of mailers. Some that will fit 1-2 and some that will fit 5+. I'd gladly pass them on..