Here comes Capt. Econ

When people think about economy, they would think Wall Street or the Stock Market. When I think Economy, I think trade and exchange rates, real world or virtual. Of course this is a shallow lead-in of what I'm talking about (no witty humor on Mondays sorry) is Virtual economies of many MMOs.
A lot are very similar in a sense so I'll stick to major markets of World of Warcraft (WoW) and Second Life. These two are different enough. Second Life conducts in shops and off-line trades, while WoW uses the auction house to trade between players in EBay style bidding. Although, both deal with a human player interacting with another human player for an item in exchange for game currency (or in some more illegal trades, real-life currency).
The only real difference between the two is that WoW's auction house trading is conducted within the virtual world and only the virtual world. While Second Life users can exchange through an Non-Player-Character(NPC) style shop which is created by another user to sell their mechanise within the game, quick and simple. The other way is by placing the item on "Xstreet" or more commonly known as SLExchange. With SLExchange, it's "offline" by not dealing within the game, but can just as quick and easy as the NPC shop method. SLExchange just mimics Amazon.com rather than EBay by not including bidding.
Another big difference is that in Second Life, when someone creates something, they "own" it and are able to copy and redistribute it as much as they wish within the game, to whoever. Therefore, When someone buys something from the shop, the item will not run out of stock because it contains endless copies within it, and same for SLExchange. WoW, on the otherhand, does not give ownership to anything the player "has". If a player finds a great item within the game and wants to sell it, they only have that one item and after it's sold, there are no more until another is found/bought. Which is why the EBay method is perfect for that economy, EBay in real life is used by human beings with (normally) only one item and bidding for it would make the price go higher and make the item worth more.
Out of both, I would think in a perfect society, the Second Life way of things would be so much better, but due to such a mess the economy is right now, the WoW style would somewhat mimic the economy and fall. At this time in the way of the market, I could only advise Second LIfe's gentle (and hippie) method.