Alright I have to say so myself that this way of making money requires research but if done right, can make you serious profits. How you may ask? Well, theres a small insignificant place on the official WoW website that can make you more gold than you ever dreamt of - the patch and test server notes.
By studying these notes, you can speculate on the WoW economy after the patch is put into place. You’d be able to tell which items are going to go from useless to super-expensive allowing you to stock up the item in big quantities before the patch and then selling them afterwards when the new patch is out!
If you’re skeptical of this method, remember when Blizzard implemented the runecloth turn in quest for reputation increases? Some smart people (including me 
) knew that they could make some serious cash stocking up with stacks of cloth. And now look! Prices have almost tripled . Darkmoon Faire was another great (and recent) example of speculation being put into work.
[...] Speculate: make serious WoW Gold [...]