Capitalism
Property owned by individuals, not by the government is often called private property. In theory, under competition, in capitalist free market economies, prices move up or down according to the availability of products and how many people want them. In most countries there is some regulation (trade laws) and some planning done by the government. They are sometimes called "mixed economies" to indicate this. Some people disagree on whether capitalism is a good idea, or how much of capitalism is a good idea.