If you payed any attention while leveling, you probably noticed a number of cooking related quests which reward you a cooking recipe and a stack of the food the recipe is for in return for gathering some reagents.
Well, in my experience, those recipes can sell for a nice sum on the auction house. If you are leveling alts and you have no interest of getting all the recipes for them, you might consider not wasting those on yourself and selling them for some extra cash. If nothing else, it will slightly decrease the pressure on your mains pockets. You can always buy the same recipes back when you are rolling in millions from all these awesome tips you are getting. :D