In my opinion, nothing has ever come close to the rich economic system that emerged naturally in Diablo 2. Maybe it just hit me at a good time in my life, towards the end of high school.
I spent probably half my time playing that game just doing arbitrage trading. For example a sorceress or necromancer would always give you 4-5 Perfect Skulls for a Stone of Jordan (SOJ) ring, and you could pretty easily buy an SOJ from a barbarian or amazon for 3-4 Perfect Skulls. Through nothing but these trades I was able to go from a couple SOJ (the most valuable 1x1 item in the game) to about 40 or 50 over the course of a few months.
I spent probably half my time playing that game just doing arbitrage trading. For example a sorceress or necromancer would always give you 4-5 Perfect Skulls for a Stone of Jordan (SOJ) ring, and you could pretty easily buy an SOJ from a barbarian or amazon for 3-4 Perfect Skulls. Through nothing but these trades I was able to go from a couple SOJ (the most valuable 1x1 item in the game) to about 40 or 50 over the course of a few months.