This looks pretty awesome! Definitely useful for mmo devs. A couple of suggestions:
A category system, where you can isolate different items based on their type. i.e. weapons, armor, consumables, etc.
A filter system. You seem to have the basic structure with name, price, level, seller. Being able to filter based on those terms would be a nice touch. Maybe even being able to add more parameters if that were possible.
That’s my take on it. This is great work, keep it up! =)