Box made of paper, with lid.
This box is made of paper.
There is marks in the "outside leftover paper" to help see where to fold (cutting with tabs helps use them). The cut is very precise, and could be too tight if misaligned when glued. A plywood box (such as a simple TypeTray) of the same size is a great guide during folding and gluing. Just fold the box against it. Accurate quick and easy.
A paper creaser (or bone folder) is also useful.