Economically speaking, the value of an object or service is the price it would bring in a fair, open market; the item's "buying power".
Intrinsic value is value which is inherent in an object: A one-ounce gold coin has intrinsic value because of the gold it contains. Even if its issuing authority (such as a government) were to fail to honor the coin's value, it would retain its intrinsic value.
Extrinsic value is value which arises because of an agreement: Although the intrinsic value of a €100 note is not much more than the value of any similar piece of paper with a pretty picture on it, it has a practical value (an extrinsic value) of €100. If its issuing authority were to fail to honor the note's value, it would soon become nearly worthless. This happened recently with the Argentinian peso.
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