How do you make money in nine chronicles?

So, I'm curious, how exactly do players make money in the game 'Nine Chronicles'? Is it through completing quests, defeating bosses, or is there some sort of in-game economy where players can trade items and resources? Is there a way to invest real-world currency into the game to enhance your character or progress faster? And finally, are there any risks or precautions players should be aware of when it comes to earning and spending money in the game?