If you have been/plan on playing Neverwinter for an extended period of time, heres a tip that many people may not have thought about. At level 52, the Adventurer's Reward contains a coupon (single use) for 20% off of 2 characeter slots. This brings the total from 500 to 400. 400 zen is going to run you 200k AD and like I said, will allow you to purchase 2 new character slots which is 100k AD per character. It takes me about 45 minutes to level a TR to level 11 which allows for invocation. The investment is then when you character hits level 23, you can do the quests in Neverdeath Graveyard which grants you a Special Proffesion Pack which you can then sell for ~90k which means that character only cost about 20k AD (after AH cut). It also gives you another character which gets AD from invoking and another character which can do proffession which will also give you AD.
This is just a little hint about creating a more profitable future. I know it was a large wall of text but maybe it can help a few of you out.