You craft them from john barricade in NLC inside big ben tower (manual) and spindle in omega sector (actual item).
Ah, it depends. If you actively spend NX on gachapon and hoard lots of ores, you will most likely have numerous fs crafting materials such as taru totem, tiger head, steel plates etc. In this case, crafting it your self will save a bit of mesos vs buying it from FM. However, if you are trying to purchase the materials for crafting purpose, you will have to use multiple owls and/or bargain with sellers for a satisfying price. At this point, just buying the crafted one might save a lot of time and stress at the cost of extra mesos.