Yeah, I know, some guys have already covered this - Cold was the first I saw but Kuja also wrote about it earlier this week too! So why am I covering it again? Well, I added a little spreadsheet to look at the costings (I am an Accountant by trade, you know!) and I thought it might add a little to the information that is already floating around the blogosphere.
As you can see, it's a pretty basic spreadsheet - just for my personal use but I tidied it up to have it's picture taken :) I just bash in the sell prices for the mats when I'm thinking about crafting & it easily tells me whether to buy ores/bars or the enchanted thorium ready made. On the day I did this screenie, dream dust was pretty high priced so I started looking for cheaper sources of dream dust.
Now Dream Dust disenchants from armor items level 41-50 with itemlevel above 46 giving on average, 3.5 dusts, so I went looking at the AH to see what I could find. I mentioned wow-professions.com the other day & as Stokpile pointed out in the comments, it's a great site for finding out what not to craft for profit! Everyone levelling a profession will be producing 5 or 10 x itemZ so although there's no point crafting them yourself, they do make excellant disenchanting fodder as most levellers just shove them on the AH at silly prices to get a little cash coming back.
The following list shows some of the items to look out for on the AH at silly low prices - I usually bid on these as I'm not in a rush for them - but obviously, only if the cost is less than the current 3.5xdream dust cost!
3.5 dusts per
Thorium Bracers (BS lvl 255)
Imperial Plate Bracers (BS lvl 270)
Runecloth Belt (Tailor lvl 255)
Runecloth Gloves (tailor lvl 275)
Wicked Leather Bracers (LW lvl 265)
Diamond Focus Ring (JC lvl 265)
Simple Opal Ring (JC lvl 260)
1.5 dusts per
Ruby Pendant of Fire (JC lvl 235)
Truesilver Healing Ring (JC lvl 240)
Nightscape Boots (LW lvl 235)
You can also apply this principle to any of the enchanting mats - Illusion Dust is also expensive so whilst I was bargain hunting, I made a note for that too - it D/e's from items lvl 51-55 & they give 1.5 dusts on average. With the current cost at 10g per dust (eeek!) that means bidding on the following at less than 10g should make sure you get your mats much cheaper!
Frostweave Pants (Tailor lvl 280)
Runecloth Boots (Tailor lvl 280)
Onslaught Ring (JC lvl 280)
Thorium Boots (BS lvl 280)
Emerald Lion Ring (JC lvl 290)
The beauty of the Illusion Dust bargains is that if you don't get Illusion Dust, you get either Greater Eternal Essences (which is what started this bargain hunt!) or Large Brilliant Shards (which relates to my Timbermaw post a few posts ago!).
I used this idea to get cheap Heavenly Shards at the start of Cataclysm - LW'ers in particular were having to make a lot of Cloak of War to get their last few points so they were dumping them on the AH. I was buying them at maximum price of 35g when the Heavenly Shards were selling for 50g upwards. Have you got any favourite items for disenchanting (besides the JC shuffle stuffs). Maybe I missed something major off my list above? Let me know!