I had 11 characters slots when I logged in because I purchased the 3 from the marketplace.
Purchased one doll of character. Clicked it, logged out and saw 12 slots. Logged in, bought another. Clicked it, logged out and saw 13 slots. Logged in, bought another. Clicked it, logged out and saw 14 slots. Logged in, no more for sale.
After you purchase doll, place it in an empty inventory slot and click. You will then need to log out of game and when you log in again, you will have your extra slot. Hope this helps!
Aye - this is exactly how one uses this doll. I purchased it on Cazic server, right clicked it in an inventory slot, and completely logged out of the game (/camp desktop). Then I relogged in to EQ, and voila! 8/9 character slots on Cazic. Camped and went to Drinal - 0/9 characters. So it appears that the extra slot applies to all servers. I am LOVING this (I am an incurable alt-aholic :P )!!!
Is this bugged, says you can get extra chacter slot up to 3. So I decided to give it a try well like the others posted below no extra slot I am still at 8/8. Anyone know this works?