well in the case of py mods many mid tier items arent worth( market price ) the sum of their components
and there were items with nearly no price( very cheep) that are actualy sorta expensive (presured air /water tailings)
in the case of those yes they are made from nothing BUT you need power to make them and they are made preaty slow so you use lots of space , in the case of tailings you can dry them and get coal dust and chrome+ some iron
