In Nightmare and Normal, crafting mats were so underpriced on the AH, they were nearly free. What about Inferno? There's no way to check now, with commodity auctions being turned off, but should I be vendoring my crap Inferno blues, or should I be salvaging them?
Right now I am vendoring all items that are not level 60 requirement. These generate the Hell and lower essences, which I don't believe are going to have a lot of value.
I'm salvaging all level 60 items to get the Inferno Mats, which I believe will have a lasting value.
Agreed, only lvl 60 mats are worth more on the AH than the vendor sale price. Top crafted items are only 1 tier below the top dropped items, so there will always be demand for these mats. Once you reach inferno you soon discover 95% of loot and mats are worthless junk in hell and below, the only items that sell for 100k+ on the AH are inferno drops/inferno lvl crafted gear or maybe late hell lvl 58+ rings e.t.c with perfect stats.
You'll see the price difference between the vendor value and market value, once that part of the AH is running again.
There are a lot of lvl57+ items or on rare occasions even lower that are very useful in inferno, although they do need to get quite a bit luckier on the rolls to be worth using. Sure they have lower armor and probably lower max possible stat rolls, but they can still roll high enough stats for the normal person running act 1, 2 and even 3 in inferno to consider buying them. Then again, spending gold to craft said items is probably not worth it, and even if it is, the value of crafting is low enough for the gold to be the real issue and not the materials, causing materials to be cheaper than vendor price.
In inferno, I suppose enough people are actually crafting, making the materials somewhat more expensive than what the vendors would pay. Though still gold is a very very major part of the crafting cost. Looking at the helm of the command legendary, about 1/2 of the crafting cost is the raw gold cost, with other 1/2 being mats. In lower difficulties, the cost of the mats is negligible compared to the gold cost.
Bottom line: If it requires level 60, salvage. Otherwise, vendor. On some rare occasions it may be worth it to salvage items lower than level 60, but they are rare enough to not be worth bothering with.
Considering crafting will be buffed at some point in the nearish future, as well as legendaries being buffed (so crafting them is more worthwhile), inferno mats should go up in value. I salvage all 60 items I get not easily sold for over 50-100k.