From Practical Economics
The merits of a price system functioning within the free market are overwhelming in moving scarce resources to their most efficient use in a fair and equitable manner.
Market economic systems embrace the components of a price system to effortlessly move resources. Command economic systems ignore the components of a price system causing resource inefficiency. This is not to say that a command economy does not have prices, but that price is determined by decree and not supply and demand.
Because of this, a command economy has the problem of allocating the time, money, labor and capital necessary to meet the millions of diverse wants and needs of a population. In trying to do so, the command approach is faced with the staggering proposition of trying to digest literally millions if not billions of pieces of information that changes every second to determine prices.
History has shown the disastrous results of fallible men trying to indeed figure out the dynamic needs of the people through a command approach to prices. The miracle of the market framework is that the same complex situation is quickly and easily solved by a free exchange price system without fanfare or warfare.