Rather than going through all the trouble of planning the design and management of an uber-realistic economic system, I've thought about possibly using the dutch auction method to sell objects at market prices in stores.

Basically, what I'm thinking is that, rather than actually selling objects to NPCs, you can rent store space from them for a small fee based on the object's weight and size. The player sets the beginning selling price (which must be greater than the storeowner's fee). If no one buys the object at that price, then after a certain period of time, the storeowner sells all such objects to the goblin market, the center of economic activity in the mud. This basically gets the objects out of the boondocks. The price of the object increases by the percentage kept by the goblin merchants and possibly the storeowner's traveling cost. The travelin cost would be determined by the levels and sizes of the areas the storeowner has to pass through to reach the goblin market.

If there are other objects exactly the same as that one at the market, then the prices of the two will be averaged. That way we could keep track of types of objects, like players are used to, rather than individual objects.

At the goblin market, prices gradually fall for each object to a minimum value equaling the percentage kept by the goblin market. (Maybe if a craft system is implemented, the objects would eventually be sold off as raw material). If you wait too long to buy the object you want, someone may buy it before you do. In a mud where equipment is competitive, and where the goblin market truly is a center of economic activity, this will mean that individual objects will (I hope) sell for their true value at any given moment in time.

Now I've got to decide whether to make merchants actually travel to the market. That would make it much easier to determine their traveling costs, because it would be equal to the average amount they could have sold had they been in the store during that time plus the average amount they lose to theivery and such along the way.

Eventually, it all comes back to the player. The goblin market handles all such accounts; the player goes there and requests he or she be paid. The player gets whatever is left after the storeowner and the market get their cuts. The original gross is determined by whatever amount was left after the most recent sale of that type of object. Thus, the player can get paid almost immediately after selling the object, though there is an associated risk. This allows for some limited profiteering.

Also, the player could forego selling to the storeowner and sell immediately to the goblin market instead, if they don't mind the inconvenience of traveling there with their load. It would often be more worthwhile to storeowners because they would be carrying more at a time than most players.

Interesting...so it would sort of be the opposite way around to a regular auction? The item would start off at a fixed price, and then keep dropping until someone bought it?

I think I might have to borrow that idea and combine it with the more regular auctioning system I've been planning. Thus a player could put an item up for auction at a set starting price, and over time the price would drop until someone put the first bid on it, at which point the auction would begin normally.

There should probably be some sort of up-front payment for each item entered into the auction as well, to stop players entering stuff at really high prices and then withdrawing them once they start dropping.

Well, in my system, I could make the case that the player doesn't have the right to withdraw the object from the goblin market. Because of its influence, it has gained legal protections from such behaviors. (Bureaucratic red tape is good for something after all.) So basically, the player can play around up until the auction actually starts, but then they are stuck with the results. They could always buy the object back themselves if they want try again, but that's fair behavior, as the goblin market and storeowner still get their share.

The one thing that really worries me is game theory behavior. Such a strongly market controlled system would require more careful design and management of the equipment outflow. I think a broad auction system will magnify any imbalances in how much of each type of equipment there is suitable for each type of character. I'm not sure what the best way of balancing equipment is. It is something I'd like to be market controlled as well, but will that simply shift the problem elsewhere rather than dealing with it? At some point things will have to be managed by hand, maybe it would be best to do this while it's still easily quantifiable.