Im sure there is many guides with every profession on this site on how to shuffle ore, and make tons of gold with various professions.
So i was on my enchanter lastnight and looking up old chanting mats from Wrath. And noticed that Abysal crystals were going for 1g50s on the AH.
Abyss Crystal - Item - World of Warcraft
And decided to look up infinite dust: Infinite Dust - Item - World of Warcraft
To my surprise a stack of infinite dust is going for on my server 110g per stack. So using my chanter to Break down the Abyss crystals and turn them into dust and flip a 1g50s
buyout into at 100-105g profit was rather delightful.
Step 1: Buy all the Abyss crystals off the Auction House for 1-2g each
Step 2: Abyssal Shatter - Spell - World of Warcraft
Step 3: Profit $$$
And if their isnt any crystals on the Auction house, at lvl 90 Goto something simple to farm like Naxx kill some bosses DE their loots. and flip it all into infinite dust
PS: i noticed the Greater Cosmic Essence - Item - World of Warcraft in stacks of 10 for my server were only selling for 15g. but im sure if you wanted to improve you profit you could just post these aswell.