A3-sized papers would be better, you can make a bigger target from those. But since A4 is widely used in the office, i don't need to be choosy... since it's free anyway. ;)
So here goes...
Step 1: Materials
2. old ring binders/file folders (or a strong, thick cardboard)
4. cutting mat (optional)
5. rubber cement
6. cloth from old t-shirt of whatever you could find
7. 2-inch duct tape or filament tape (those with fibers)
8. 2-inch packing tape (the strong, clear types are preferred)
9. metal ruler or anything straight that would serve as a cutting guide
10. straw or any flat rope
11. old paint brush
Step 2: The top and bottom shell
Step 3: Stacking them up
using a straw or any flat rope, tie it around the stack to initially compress the stack, pulling it tightly before you make a knot at the stack's corner.