One of the things that I started doing almost ten years ago was buying canvas panels, paper, and cutting paper down to fit into standard size boxes, envelopes and frames. It has the benefit of making it easy to ship and to frame work both for my collectors and shows.
|Here's a diagram of how I cut large sheets 22"x30" sheets of Rives BFK print making paper. The diagram also includes standard sizes for frames.|
It also has the added element of being able to buy stiff cardboard envelopes from companies like Uline.com. I also save the boxes that the envelopes and other packing materials come in so that I can use it for stiffening the packages.