The term "command economy" refers to an economy where the government determines what goods should be produced, how much of them should be produced and the price these goods should have. This is quivalent to saying that the government controls the whole economy. This is a common feature of communist regimes. On the other hand, a market economy is one where most aspects of the economy are determined by market pressures, and by the law of supply and demand. However, most market economies still have some level of government involvement.
Some of the ways in which people benefit from an economy that moves away from a command economy is that a market economy usually has more variety of products. This is because people are more interested to enter the market, as any product can become extremely successful if it is popular among customers. Moreover, this usually helps the problem of prices as the availability of options often provides similar items at many different price points. Finally, another benefit is the fact that, because market economies encourage competition, businesses that are inefficient usually fail, allowing better businesses to rise.