Here is a link to an article posted on MMORPG.com concern the market system.

Here is a blurb from that article below:

Assuming that you are just starting your career in Aion, you probably won't be interested in buying a lot of stuff right away, and you certainly won't be able to afford anything of high value even if you wanted to. But there is plenty of opportunity to sell items and start making some decent cash from the very start.

There are four ways to sell items in Aion:

* NPC vendors
* direct trade
* private shops
* trade brokers


Link to full article:
http://www.mmorpg.com/gamelist.cfm?f...ame=253&bhcp=1