Well if you have no money then your best bet is mining, easily.
Farm some Copper and Tin Ore. Or if you're lazy you can probably do it with just Copper, however Bronze Bars are far more profitable.
Here's a website that shows you the best routes to take for farming Mining Mat's: Http://www.wow-professions.com/wowguides…
3-5 stacks (60-100 Ore) of each type of Ore should be enough to get started. Smelt them all together into Bronze bars and stick them in the Auction House.
Once they've all sold and made some money you can stop actually going out and mining. This next bit is the easy part, although it can get a little tedious.
Now that you have some gold you can start to buy Ore on the Auction House. Compare the price of Ores to Bars on the Auction House and if they Ores are cheaper than the Bars, then buy the Ore, smelt it and sell it.Because Bronze uses both Copper and Tin Bar's you can mix and match between Ores and Bars as long as they are cheaper than Bronze Bars.
While smelting the Bronze Bars you can and eventually will be able to smelt Iron. It is possible to simply smelt Ore up to 525. So when you are able to smelt a new type of bar you can also check it's own Ore/ Bar profit and smelt those too.
I often find after a while Mithril, Thorium and Cobalt are typically the most profitable when it comes to smelting and as such should be the first Ores/ Bars you check when available.
Aslong as you try to everyday during prime time (3-8pm I find are the best times for listing Auctions) list you Bars you should be well on your way to making money.
While this depends entirely upon your server's own economy, I find that once you've hit 12-15K you can afford to level Enchanting or Jewelcrafting which are the two most profitable professions.