Explain how the value of an item is determined?

supply and demand as well as materials and how much they can charge. so if a company has a lot of something but not enough demand they want to sell it for a lower price to get rid of the stuff, but if there is less supply and more demand the price goes up. also things like cars or computers that have relatively expensive pieces or are expensive to make cost more. diamonds are priced high because a company called da beers has a monopoly on them and will only release a few at a time to make them seem rare. they will pay like $20 for a rough blood diamond in

Africa cut it and turn around and sell it for $1100. why? because they can