Since I have only 2 days data from the Auction House I cannot make buy and resell businesses, so I'm bound to my "secret" trade, that will be revealed tomorrow.
Today I made a choice that was not profitable financially but still worth it. I bought a portal to Darnassus for 1G. I quested in the elven world and it was beautiful. Not from the point of view of profit, but landscape. I think the elven race got the most love from the creators of this world.
But a goblin trained mind can find profit even in such a landscape. I took the free boat ride and sailed to Menethil Harbor, getting the flight point there, so now I can travel between the worlds. Landscape and trade routes, for only 1 G. Fair trade.
I reached lvl 15 by questing with an elf I met randomly. Luckily Darkshore is full of kill X and find Y quests that can be completed together (opposed to collext X of Z quests which I hate)
My current wealth is 48G. On lvl 15 and day 3, without finding any lucky bargain on the AH. Just by proper trading. Spent it all. Mostly on invesment, but spent 6G on gear and bags. It's also investment: into faster levelling.