Umm depends on the item but maby 100k+ would be "mass" for iron ore. Really your just doing people a convince by getting so many but then im not sure what they would need 100k+ for unless they want to do alot of smithing.
So im not even sure many people would want to buy 100k+ but who knows maby make a thread now and see if anyone is interested. Its not like other items like bronze arrows which are hard to get alot of in the ge because of limits ect.