According to datamined info the highest level craftable gear, level 10 Exalted, will require the following materials:
Valuable Component x 30 (normal quality Inferno items)
Exquisite Essence x 18 (magic quality Inferno)
Iridescent Tear x 6 (rare quality Inferno)
Fiery Brimstone x 3 (legendary quality Inferno)
What do you think about the cost? Considering the amount of gold testers are able to farm in 1/3rd of Act 1, I don't think the gold cost is all that high. It will add up over time, but the salvages are another story. If legendary items salvage into multiple components then part of the problem is alleviated, but the fact remains that these are legendary items in the hardest difficulty in the game. I doubt that they will be very common, salvaging them even less so. Based on the 50k crafting cost, I imagine prices on Fiery Brimstone will be VERY high. I hesitate to guess, but I would put them at anywhere from 300k to 1mil. Maybe legendaries in inferno drop like candy, only time will tell.
My understanding of crafting is that items will have 1 or 2 specific baseline affixes, like enhanced damage or crit, and +# random affixes. This makes crafting a true, and fairly extreme, gold sink. You could end up with something that is junk compared to an Inferno legendary or something that is much better. Is there any evidence to the contrary? Could crafting at a high level be more akin to D2 Runewords, with set affixes within a certain range? A safety net for the more casual players?
At any rate, the crafts need to be far ahead of Inferno legendaries to really justify the cost. Do you think this will be the case? Will there be inferno-only affixes that make legendaries more desireable?
I can't imagine what a perfect Exalted level craftable item would sell for on the GAH/RMAH... but it must be astronomical.