The cheapest I've seen any crafting gear, i170, on my server's board has been in the 300-400k range, for NQ. That's more than the price of a t4 Materia, though well under the price of a t5 crafting Materia (which started, last I looked, around 2 mil and quickly went up from there; that was historical pricing though as I've never actually seen any t5 crafting Materia for sale).