So the method I used is or may not be the most profit, but it is very predictable in terms of giving you an idea of how long it will take you to get a specific amount of money.
At level 38, I had 5 gold. At level 40, I had the 90 gold plus 14 extra gold for my level 40 training. Once all was done and finished, after spending almost all of it, I had a little more than 2 gold.
In Desolace, in shadowprey village, there is a troll on the dock with a repeatable quest. I suggest you make your way there and talk to him and after that use wowhead to see how to complete it. It is stupid easy, but does require some leg work.
I started Tuesday and dinged 40 on Sunday of the same week. I did it daily for four Elixirs, 2 hours or 8 stacks of shellfish. On Sunday, due to the congestion of people doing the same quest, I used 12 Elixirs to get the same amount of shellfish on previous days.
- classic auto quest turn in add on
-Elixir of water breathing
have a guildy make these, buy the mats off the auction house and each elixir requires 3 empty vials, so make sure to provide the vials too as that can be expensive for the guildy.
This is no doubt very slow and frustrating, but it is very rewarding.
Kill the lobsters along your path from cage to cage. I tried the freezing trap/feint death method, but it only works the first round of cages. You will need to clear the lobsters so go ahead and do it. Also, I found that the more lobsters I killed outside the cages, the odds of looting shellfish from cages was higher.
You only need to find about 3 - 4 cages and create a loop with them. Respawn time is roughly 2 minutes. Once you make yourself a loop, you will get the occasional person that messes up the routine, but for the most part it is not too bad as the people grinding mount money will have similar loops in other spots. Most people looting the cages are just doing it to get that first turn in done and then they off on their way to other quests.