You haven't done the three dungeons yet? You do those shortly after you get the airship pass as part of the story line. You cannot do the dungeons until you reach that point in the story (At which point it will flash on your screen that you can now access XXX dungeon).
I think there is more story line quests for you to do. And the ones after the airship give you a lot of exp. You can go from 15 to 19 just through those quests and the three dungeons.
Oh, and there is a marketplace, but you can't access it until very late in the story line chain (near the end of what is available for the Beta). You get access to the Retainer, and you can give them items to store, and have them sell items on the marketplace for you. You'll probably be level 20 by the time you get the Retainer.
Actually, I was wrong. You get Retainer access once you complete the 3 city dungeons.
Edited, Jul 6th 2013 8:28pm by TirithRR
Can't sleep, clown will eat me.