The value of silver bars depends on the value of silver, at the time of writing silver is $29.09 per troy ounce so your bar would be worth $29.09. However, precious metal prices are volatile and change on a daily or even hourly basis.
It's not a coin, it's a bullion piece or "round". Its value is tied to the spot price of silver, currently about $12-$13 per ounce.
It's a 2000 one-ounce Silver Eagle bullion coin and as of today is about $18.00
A 2002 silver eagle is worth whatever one ounce of silver is worth. At the time of writing, an ounce of silver is worth about $22 and a silver eagle would be worth the same. However, silver fluctuates in price on a minute to minute basis.
It will be worth the value of silver per ounce. Currently about 30 dollars.
The current spot price of silver is $31.71 per ounce, that's the value of this coin.
A "colorized" silver eagle has no numismatic collectible value, but it's still one ounce of silver that's worth about $30.00.
It's a 2005 one-ounce Silver Eagle bullion coin and as of today is about $18.00
The U.S. Silver Eagle is one troy ounce of pure silver. As of 22 January 2013, it's worth $32.
From your description the coin is a Americain Silver Eagle that is made from one ounce of 99.9% pure silver, value as of today is about $19.00
It's still 1 ounce of silver that's about the only value to it, unless you find someone that wants it. The silver value as of today is about $15.00.
The value of these bullion pieces is normally based on one ounce of silver, which currently has a spot price of around $14.
Its value tracks the spot price of silver, currently about $13 an ounce.