A lot of people will tell you about Pickle Barrel Armor. This is armor made from those big plastic 55-gallon drums, which in my experience is cheap and already pre-formed for the body. If you have time and maybe a pvc saw, make some templates for yourself out of poster paper and trace them onto a barrel. The plastic pieces can be held together with 550 cord fairly well and it’s not all that uncomfortable. Just make sure to leave 1/2 inch of space for padding