Here in the UK they haven't figured out how to recycle juice boxes yet (something to do with the multiple layers of foil, film and plastic) but they are just too neat to throw away. I am also a hoarder of magazines but they just won't stay upright on the shelf.
Using a couple of empty juice boxes, a pair of scissors and a stapler you can fashion a simple holder for any size magazine. I'm going to demonstrate with my back issues of Make: magazine.
Step 1: Cut open your boxes
Hopefully you have rinsed out your juice boxes. Don't wait until the juice dries onto the sides of the box - rinse as soon as you finish the juice and definately don't let a small amount of juice ferment in the bottom and grow into a juice slime mould creature.
Start by cutting the wings off the top then cut the whole top off.
Next cut down one side (the narrow side) of each box but don't cut it off at the bottom.