How they fix value for money?

How they fix value for money?
This is a very broad and obscure question...but I'll make the attempt to the best of my ability.When you consider the value fixed to money, currency, and coins, we must first consider why and how it came about in the first place.Before there was money, there was the less efficeient system of bartering. In order to obtain a good, a man was forced to trade another good. If a man wanted a t-shirt, he might have to trade a book. However, the man trading the t-shirt may not want a book - several other trades would first need to be made to acheive the good sought.So a new approach came about - money. But money has gone through many stages to get where it is today. Food was probably a form of money at some point in the history of society. As was gold, silver, and just about anything else you can imagine.Money's value is based on solely the CONFIDENCE a society has in it's ability to obtain goods and services. It is entirely socially determined.Forms of money can be socially unaccepted. Take for example the $2 bill. Society preffered collectively this small demonination was useless. The treasury stopped printing $2 bills years ago.Another example could be the $1 coin. People have rejected the dollar coin - which is why you don't use them often, if ever. But the treasury still makes them because they last much longer than a dollar bill. Whereas a dollar bills "life expectancy" is about 18 months, coins can last nearly 30 years.How is a value fixed for money? Simply put - the confidence society has in it's ability to be traded for goods and services.