Im predicting with the lack of an Auction House. Consumables/Mats are going to be where the gravy truely is.

Armor and Weapons are definitely not going to be as widely sold and purchased since any selling/buying will take place in a smaller circle of players. Once these players max out their characters. There wont be as much movement of these types of items.

Beware of Trade Guilds. They have good intentions now but theyre doomed to become places of inflated prices and gold pinching. Auction Houses have long been plagued by Re-sellers and Trade Guilds will be like a moth to a flame for them. I would not be shocked if items end up moved from Trade Guild to Trade Guild steadily increasing in price. Unfortunately these Trade Guilds will also be one of the few places that youll be able to look for things you may not be able to acquire through your normal Guilds. As well itll be where youll actually be able to make a decent coin for your consumables/mats. They will be a necessary evil.