I've come to realize the quickest way to make money (legally) in Warcraft is to do the daily quests. Now, the trouble is, at level 80, many of them can take considerable time. I've noticed that the daily cooking and fishing quests have some that are quick and some that take longer. For instance "Jewel of the Sewers" can be done in a couple minutes, while the Ghost fish or the one from Wintergrasp can take much longer.
My goal here is to list quests that take just minutes but reward a good amount of gold. I'll try to list them in a route that makes sense as well.
1. Fishing, Jewel of the sewers
2. Cooking, Cheese for Glowergold or the wine quest.
3. Argent Tournament, Kill the 15 cult members.
4. Coming soon...