Would it not be cheaper to make it from scrap wood and 4 nails, with only a saw, a drill, a hammer and maybe a chisel needed? I think doing so might significantly lower the costs.
I think this idea of replacing the plastic with wood would remove the need of an expensive piece of machinery and of using electricity to power it. If it can be done with a cheaper tools and cheaper materials (relative to where people live), a lot more disadvantage (a.k.a. dirt poor) people will be able to afford them and use them to improve their living conditions.