Limit each player to buying a max of 20% of anything.
Thus someone post 10 million minerals of something, each player is limited to being able to only buy 2 million of that mineral. And allows the other 8 million minerals being able to be shared with 4 or more people.
This also prevents a single rich player from buying out the market or abusing the food market by raising the price single handily.
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SPARTAN240OP