In democracy, each person gets one vote equal to every other. The votes are basically free, but some rules must be set up to ensure this. The free or open market is somewhat considered to be democracy of commerce. To take this to the extreme:
There would be a number of businesses equal to the number of citizens, each business owned and run by exactly one citizen. There would be no employees. All needs of the business that could not be completed by the owner would be outsourced to other businesses, surely creating the need for a lot of very specialized businesses. Government oversight would be needed to ensure that no mergers or pseudo mergers occur. Every business runs on its own, with no collusion, and any interactions with other businesses must be proper business transactions with dollars exchanged for goods or services and the best value chosen from multiple candidates. Each business would be required to turn, or attempt to turn, a profit, and that profit would be the sole income of the owner. Oversight would also ensure that there were a number of a given type of businesses in a given geographical region.
All of this should create somewhere near the largest amount of competition possible, and really test competition’s ability to create low costs, innovation, and good quality.
This system would certainly have many problems, especially in enforcement, but can serve for analysis of the openness of markets and the rules affecting them.
An interesting modification of this system would be to force all of this at the initialization of the system, but then remove all oversight. This would somewhat mirror the entire human history relating to economic issues, except that it would certainly go very fast. Mergers would happen all over until large companies would be formed.