A tried/tested/true way for an honest newb to make an honest buck:
once you're lvl 15+ there's a couple quests in Dion that you can do...
one starts with Musician Barbado. He's to the right when you leave the grocery store. His quest gives you a music theme of the feast.
another is behind the DE fighter training building, Musician Nanarin (a de chick) her quest gives you the music theme of Solitude...(NOTE: im not sure if you should always choose new clothes as her gift to her secret lover, but it's worked for me every time)
the third one is a bit longer, but worth it. Bard Swan gives you a quest that makes you walk (or teleport) to Aden to talk to the weapon seller for a flute, then to giran harbor to actualy GET the flute, then back to swan. Swan will have you deliver it to Nanarin as a love gift. Report back that she doesnt love him and you'll get the music theme of journey, and 10k adena.
these three themes will be the base for your new business. That's right, creating and selling Music Crystals.
Inside the grocery store is Melody Maestro Octavia. Have her make you about 20 or so. the more you make and sell, the more the profit (duh) it costs 200 to make one.
now then, you can sell them for anywhere between 300 to maybe 800 each, which is an awesome % of pure profit.
how to get more themes: diverse and unique themes can help ensure you a lot of customers. you can either A) ask around when your selling what you have for different themes (ask for extra ones that you can nab for free :p) or B) there's a quest for lvl 41+ players that have done the "conquest of aligator island" quest and collected at least 10 pieces of a map. take the COMPLETED map to the weapon seller in heine to get the pirate treasure quest. find the underwater treasure chest on alligator beach (there's a pin marking it's loc on your map, and yeah it's underwater. and be sure to bring a key of thief) this chest should give you a random theme, and has been even known to drop Elven Mithril Gloves or other neat items
themes to look for: Comedy, Battle, and Celebration. people love comedy ^^
also the Dwarf in the Heine Grocery store gives a quest to get 25 wedding crystals. and Octavia gives a quest for 25 Birthday Crystals, these bonuses can easily be sold for 2k-5k each
a suggestion for a good selling location: the arena at the monster derby track. all the high lvls hang out there, and they always enjoy paying a few K for some music.
This guide may dissapoint you if you're looking to make millions....but can easily get you started on the road to fame and fortune if you master this small economic window.