OBSERVATION
In most games that I play I notice a pattern early game. Everyone throws down aluminum mines and steel mills and waits to upgrade their base. This is fine for most games, but for a commodities trading game this state of affairs should be looked at with concern.
EXPLANATION
The reason this is allowed to happen is that the pricing of raw materials (and all resources) does not fluctuate much early game. People are not punished for having no raw material collection on the map because they get through their first and sometimes second upgrade without getting into trouble with raw material pricing.
SOLUTION
In order to get the price fluctuation more aggressive early game but not blow it out of proportion later. (shorts are already super powerful) I suggest that the price of the resource stay the same at the start and there be a very small stockpile of resources on the market at the set price. Once this stockpile is close to eaten up the price will start to escalate to OFFWORLD PRICING for the resource. This is simulating needing to bring it from earth to the market.
This will still allow people to try to push through and only get upgrades, but it will allow people to take a gamble on raw materials if they think enough people are going to try to forgo the basic resources. This would open up new avenues of play and punish people for mindlessly having an early game build.