There are many factors that go into determining the price and value of a particular coin.
The following are the major factors that determine values and prices of coins:
Mintage refers to the quantity of coins produced in a given period and can influence the value of a coin: lower mintages tend to be more in demand because they are scarcer.
Even though a coin has a low mintage figure, it does not mean that it will have a high demand value.
Low demand for a scarce coin will have a negative impact on its value.
If a coin is made from a precious metal such as gold or silver, the intrinsic value of the metal contained within the coin can be a major factor in determining the value and price of it.
Condition plays a huge role in determining coin values.
A coin that is uncirculated and in mint-like condition could be worth a hundred times more than the same coin that has been in circulation and shows some wear.
Errors in a coin are made by the mint during the minting process.
But, to have a collectable value, errors must be produced at the mint, the error cannot be inflicted on the coin after it has left the mint.
Such coins are damaged, they are not errors, and are worth zero.
The more dramatic the error, the more valuable the coin.
Dirty coins should never be cleaned. Doing so will often significantly lower the value of the coin.