When making a weapon, do you make a standard weapon best quality and then add the attribute (such as Mono) or do you add the cost of Mono and THEN multiply the cost for best quality. Obviously this changes the overall cost dramatically!

Upgrades are an upgrade to an existing weapon. So you would first pay for the weapon (be it best, good, common, etc.) then add the upgrade on top.

So in your example of mono. You but the best quality sword and pay the x10 cost, then add the cost of mono on top of it.

I was taking it as the other way - all upgrades then cost multiplier. Will ask GM as that is a significant cost difference.

Redeucer's answer is technically the correct one, although your GM is free to cost items however he feels like it.

Thanks for the responses guys. I'll put it to my GM, he was interested in what others had been doing as its not detailed fully in the rules