Most modern MMOs don't have a real economy. EVE Online is a rare exception (and very much a niche proposition). Of the "normal" MMOs, then depending on who you talk to, Final Fantasy XI (released 2002 in Japan, 2003 in the West) or Star Wars Galaxies (2004) was the last to allow any significant degree of player freedom to shape the economy. Everything since World of Warcraft has locked in-game financial transactions down so hard that actual trading between players is knocked right out to the margins.
What do I mean? Basically, that the items of highest value in most MMOs cannot be obtained through player-production and in-game trading. In a subscription MMO (eg. WoW, Final Fantasy XIV), the most powerful gear will normally be obtained by players through skill-based team challenges (high-end raiding or PvP). Once obtained by a player, it is almost always locked so as to be untradeable to other players. A second tier of good-but-not-best gear is usually available via a pseudo-currency (tokens, honour, whatever) that is rewarded in fixed proportions from performing repetitive activities (daily quests, dungeons etc), often with a cap on how much can be earned in a week, and which can't be traded to other players. Consumable items are still crafted and traded, but the trend in MMOs has been to downplay these over the last few years.
This has largely come about due to the prevalence of real-money trading; people using real-world money to buy in-game currency. When the companies running MMOs realised that trying to crack down on this trade was like trying to wrestle with fog, some of them shifted their strategy to downplaying the importance of the in-game economy.
The others, of course, went into the "freemium" pay-to-win model, whereby he who spends the most real-world money has the best stuff.
What's interesting in the subscription MMOs is how the free market has acted to route-around the ever-tighter economic controls. You might not be able to buy the best gear, but in both WoW and Final Fantasy XIV, you can hire teams of players as "mercenaries" who will run you through the high-end content and guarantee you the items that drop. Blizzard don't like this, Square-Enix turn a blind eye. Various other types of grey-market activity have also sprung up around the margins to allow players to turn either in-game or real-world wealth into an advantage.