depending on your lvl determines how much you can make and how fast, when it comes to money quests you only earn a certain amount. But if you use gatherung you can make as much money as the high levels when they gather, ( getting grade E minerals and gems make you alot of money) but grade D and up are hard to find and can be difficult to get for low levels and takes much longer so collecting grade E is the best bet for money. Farming is another way to make lots of crone, again the drops get better as you lvl up more so that also limits the amoun you can ear.
hope this helps