In a lot of MMORPGs and a good number of MUDs for that matter, the economy is a faucet-sink economy such that the amount of money that flows in is approximately the same as the amount of money that flows out. In terms or ore, it can be as simple as limiting the amount of ore that can enter the world in a given time interval.

It makes perfect sense to have a finite amount of ore that can be mined from a given mine area though, but this raises a number of questions with regards to item persistence. If a sword you make from the ore is allowed to be disposed of (*poof*), then the ore that you used to make the sword would be permantly out of the game.

At any rate, I think a well-balanced economy is one that has at least a number of commodities(can be money) that is scarce and seemingly finite. In fact, I think a \'central bank\' model might be a good idea too. Each active player in the world causes money to be added to the total amount of money that can exist in the world(say it starts in the royal coffers). This money gets out to the people by services rendered(quests), and goes back to the coffers through services rendered by the state(teleporting, transport) or even taxation. If the state or NPCs run out of money, tough luck, you can\'t sell your stuff, and you don\'t get money from quests.

Then with your resource rate-limiting, rare monster drops, rare ores that you have 1 in a million chance of getting from a mine, you have scarcity of other commodities.

I think the growing trees idea is cool too.. and it gives you replacement wood in case your house burns down.