This is probably (very) old knowledge for people who sell cooking packs. For those who don't, check it out.
The Cheese Vendor
For Low Levels (Level 1+).
This is especially useful for : Players who want to develop a hefty stack of gold when starting on a new server, and Fellow AH freaks who do gold challenges.

Cooking quest (Clamlette Surprise - WoWWiki), has been changed in 3.1 and teaches (Clamlette Magnifique - Item - World of Warcraft), a level 35req cooked food which has the stats of level 45req food, and requires only Clam Meat.
Interesting recipe for cooks, isn't it ?
Let's take a look at the quest to see what items it requires.
# Giant Egg (10)
# Zesty Clam Meat (10)
# Alterac Swiss (20)
We'll focus our attention on the Alterac Swiss, as the 2 other items are mob drops.
A quick lookup on wowhead : Alterac Swiss - Item - World of Warcraft
We notice the closest vendors are in Thousand Needles(Horde) or Dustwallow Marsh(Alliance), which are still pretty far away from Gadgetzan. (Actually, "Cavern's of Time Inn Vendor also sells it." - Thanks to [sync].)
So you'll guess cooks would much rather buy them right in Gadgetzan, where they got the quest, than taking long flying paths or trips and going back.
But how are they gonna do it ? There's no cheese vendor !
We'll be the cheese vendors.
Walkthrough
We'll buy stacks of Alterac Swiss, and sell them on the Neutral Auction House.
You can do this with LEVEL 1 characters, provided you have at least the 1g60s required for a stack, and 30 copper for mail.
I-Preparation
Cheese-buying alt
Horde: Make a level 1 Tauren (or Blood Elf), park it at Thunder Bluff Innkeeper (or Silvermoon City Innkeeper)
Alliance: try Human - Elwynn Forest. {Lion Pride's Inn, buy from Bartender}
Auctioneer alt
Horde: Make a level 1 Orc or Troll, park it at Booty Bay. If you're not sure how to do this, check this :
:<
Alliance: This is a bit trickier. We'll make a Night Elf.
Here's a World Map of Teldrassil.
1.Go to Darnassus. (west of Shadowglen)
2.Once you are in Darnassus, keep heading west until the Temple of Gardens.
3.Take the portal; you will be teleported to Rut'Theran Village.
4.From Rut'Theran, take a flight to Auberdine. This should take a couple of minutes.
5.Once you are in Auberdine, take the boat to MENETHIL HARBOR (if you don't know which one it is, look for the signs)
6.Once in Menethil Harbor, take... another boat, to Theramore. Don't go AFK !
7.As soon as you enter Dustwallow Marsh, jump from the boat.
8.Swim south, while keeping away from the shore (swim in the clear water). Dodge the mobs that you encounter.
9.When you see 'Tanaris' pop up, drown yourself.
10.Congratulations! Your ghost spawns in Gadgetzan. Simply resurrect from the Spirit Healer and you're done !
II-Buying and Selling
*Using your 'Cheese' alt, buy as many stacks of Alterac Swiss as you wish. Mail them to your 'Auctioneer' alt.
*With said 'Auctioneer' character, post the Alterac Swiss on the AH. Shoot for 7g99s99c(500% return). Don't ever go below 5g (310% return).
SELLING TIPS :
-Don't sell more than 4 or 5 at a time; low supply helps keep the prices high.
-You can (and really should) use psychological pricing; with one alt, post a bunch of overpriced auctions, and with a second alt, post a few auctions at your desired selling price.
III-Reaping the Profits
*Enjoy your profits ! You've hopefully turned stacks worth 1g60s into stacks of 8g, which is 5 times your initial investment.
Final thoughts
There are few deals on the Auction House that give as much return as this one, so this will make you some fantastic gold until you're in the hundreds.
Let's think about it : it takes 2 minutes to put up 5 stacks of Alterac Swiss on Neutral AH. You invest 8g and get, worst case, 25 gold back.
That's a 17 gold profit, in 2 minutes. Everybody understands this is good use of money.
Eventually you'll hit a mark where you can start finding more worthwhile investments. But before that, there's no match.