So what we've figured out is Magical Artisan, from the Forgotten Realms Campaign Setting book gives you a 25% cost reduction when applied to an Item Creation feat used to make a magical item.
The following are all magic item creation feats that can be applied to the creation of any magic item so you can apply Magical Artisan to each of them when making a magical item.
Legendary Artisan (ECS) - Consider the base price of the item to be 25% less when calculating XP
Extraordinary Artisan (ECS) - Consider the base price of the item to be 25% less when calculating GP
Exceptional Artisan (ECS) - Consider the base price of the item to be 25% less when calculating Time to create
Bind Elemental (ECS) - bind an elemental into the item to reduce the base cost of the item
Enhance Item (ELH, non Epic General Feat) - base the DC to resist the item on your casting stat, instead of the minimum
So add 5 Magical Artisan reductions, 1 reduction from the ECS Artisan Feats, and then if you add one to the item creation feat itself add another (example Craft Wonderous Item) for a total of
.75 x .75 x .75 x .75 x .75 x .75 x .75 = 0.177978515625 x Base cost for the new Base Cost
New base cost / 2 = 0.089 is the new Cost to Craft
base cost / 25 = 0.007 is the new cost in XP
So a normal 1st level wand of cure light wounds = 1 Caster Level x Spell Level 1 x 750 GP =
750 Base CostWith the adjustments, assuming Craft Wands also has Magical Artisan applied = 750 x .178 =
133.5 Base Cost, Crafting cost is 66.75 GP and 5.34 XPThis is assuming that only a medium size elemental is bound into the item. You can further reduce the price by 5% for each size category bigger than medium of elemental that you bind into the item.
Now lets apply this to a bigger item, how about an Airship from Eberron:
Base Cost is 92000 GP, Crafting cost is 46000 GP and 3680 XPWith the above item reductions though the new price is:
Base Cost 16374.02 GP, Crafting Cost is 8187.01 GP and 654.96 XPThis also affects time to craft the item as well, it takes 1 day per 1000 GP of the base cost to make a magic item. With the new base cost it only takes 17 days to make an Airship from scratch.
For the wand you could possibly argue that you could craft 125 GP worth of base cost per hour, though there's no specific rule for this that I know of. Just that a day crafting uses 8 hours of your day.
This last example is outside the scope of my E6 game since it requires Greater Planar Binding as a spell and I doubt that can be found as a 3rd level or lower spell, but it shows how crazy this feat investment can really be.