It is impossible to say. You need to give a date, denomination, country of origin, any applicable mintmarks and a rough estimate of condition for anyone to give you an estimate of value.
The value of a silver coin is always changing because the value of silver is always changing. See the related link below for a silver coin value calculator. This does not give the actual value of the coin but it does give the value of the metal used to make the coin. This is know as the melt value.
Metal value depends on the purity of the silver and the weight of the coin. Numismatic value depends on the condition of the coin.
Since 1817, Sovereigns have been made from 22 carat gold. I cannot imagine why anybody would silver plate a gold coin, so you may have a replica in silver. Value unknown.
A Silver Eagle Bullion coin is 99.9% pure silver and weighs 1 oz per coin. The stamped value of the coin is U.S$1 however the intrinsic value of the coin is the value of the silver within that coin. If the the spot price of silver was $30oz at the time of checking, then the value of that coin would be worth at least $30 or more.
Low grade circulated examples of this coin have a values of $70.00 to $90.00 for the most common variety of a 1817 Capped Bust Half Dollar. Foe a better idea of value have a dealer or collector grade the coin.
Please take another look at your coin. It almost certainly will have a picture of James Madison and the dates 1809-1817 or James Monroe and 1817-1825, and the back will have an image of the Statue of Liberty. That means you have a modern Presidential $1 coin. Hundreds of millions of them have been minted, and they have no added value.
The value of an uncirculated 1999 Silver American Eagle Littleton coin fluctuates based on the market for silver. However, a coin can be expected to have a value of about $40.
This coin is most likely worth the silver value.
No, there is no silver in a 1817 US penny.
1848. Silver. Twenty. Dollar. Coin
The 5 coin proof set has a value of $6, the 10 coin set has a value of $15 and the 10 coin silver set has a value of $48.
It really depends on which coin it is. Is it a US silver dollar or dime? There is a big difference. Is it a world coin? What country is it from? All of these things matter when figuring the value of a coin.