How much gold does it take to level up each crafting NPC?
If I want to unlock all recipes, how much gold will it cost me?
I think this post need an update for anyone looking for up-to-date information. With the patch 1.0.3, the upgrading cost of the Blacksmith as been greatly reduced. That said, the Blacksmith tier unlock costs break down like this, still actual for 1.0.7 and 1.0.8:
Normals tiers
Nightmare tiers
Hell tiers
Inferno tiers
This puts maxing the blacksmith at a total of 173,000 gold and some cheap books. Since there is not modification for the jeweler, to maximize both artisans, you need:
Individual recipe level costs can be found within the links for each Artisan.
So in total, 733,000 gold is required to unlock all the recipes.