A great way to make some easy gold in classic WoW is to sell vendor recipes on the AH. There are a TON of recipes that are sold by vendors, and a large number of these are in limited supply, which means that only one will be available at the time and other players have to wait for it to respawn. This will make the AH the only place to get it and you can sell it for MUCH more than what the vendor sells it for.
Helping players save time is always profitable
Players will always be willing to pay to save time. The recipes are spread all over Azeroth and some are only available from really annoying to get to recipes. Couple this with limited supply and they are actually quite hard to get on your own. Paying extra to just get them from the AH will save you a lot of time, so that’s what happens.
My experience so far
I’ve been checking in on recipes when I am at a vendor and I’ve flipped a small amount. I’ve most often been checking alchemy supply vendors as that is the profession I have been using most. There are strong recipes for most professions though, and you should not be limiting yourself to one profession.
Limited supply recipes are the most valuable
The limited supply recipes are usually most valuable. They are much rarer and thus the supply is generally much lower. Some of them like Runecloth Bag only spawns from a single vendor and is typically camped constantly. It sells for just 1g20s for the vendor, but on the AH on my realm it goes as high as 30 gold!
To find the best recipes to target look at profession leveling guides as well as which items are most useful in end-game content. Both will show you the way. While you are out in the world you should just check any ” supplies” vendor you see to see if they have recipes in stock and to check if they are valuable. That’s what I have been doing.
My TSM group includes every vendor sold recipe in the game. I had some issues with vendorbuy disappearing so I use 5 times the vendor sell price, which is the same price you can buy it for. The minimum profit is 30% and we just try to post one of each recipe. The settings assume that you are buying the recipes from the vendor, so don’t use the default shopping operation to try to flip these from the AH.
Now go out and hunt some recipes!