I'd Rather Be Collecting Fairy Breath
1) This quest starts in Gludin town in the Magic Shop with Summoner Galatea. She asks you to hunt in the Windy Hill region and and kill the mobs there, Sobbing Wind, Babbling Wind, and Giggling Wind and bring back Container of Sylph Breath. It is repeatable.
2) Windy Hill is north of Orc Barracks by the Priest of Dusk. The mobs there all look the same except the big version which will try to sleep you. They are resistant to wind attacks and weak to archers. Now you'll notice that although all the mobs look alike, there are more types than what Galatea mentioned. There are also Singing Wind, and Whispering Wind. But again, they all look alike. The quest item that you'll get is called "Fairy Breath."
3) Whenever you're ready go back to Galatea to turn them in, and you can continue the quest if you wish. I turned in 45 items and got 7,615 adena. The drop seems to be every mob so it's not such a bad deal for a lower level quest.
The final reward (based on the findings below) is that you get 50 adena per item + a bonus of 5,365 Adena if you turn in multiple quest items (the bonus kicks in if you bring 10 or more quest items).