There is no such thing as a 2004 silver penny, assuming you are referring to a U.S. one cent coin. Cents are made of zinc coated with copper plating. You could have either (a) a normal cent that someone dipped in acid, etching away the copper plating, or (b) a coin that was never plated at the mint in the first place. The first is considered to be an altered coin and is worth one cent. The second is a true error and might be worth 50 cents or a dollar. However you'd have to take the coin to a dealer to have it inspected first-hand.
One Cent is the value. The US has never made a silver penny. It may look like silver or have been silver plated but it has no collectible value.
There was never a silver Indian Head penny.
No such thing as a 94 silver penny.
The 1910 1955 half penny stamp value of silver jubilee is two pounds.
Face value only.
4,002,000
A British 2004 (silver) Maundy Penny, uncirculated and in absolute mint condition could fetch up to £25 GBP. A reputable coin dealer will be able to give a more accurate valuation.
The US has never made and never will make silver pennies. If a penny was silver it would be worth more than a dime.
$10,000
It's steel, not silver, and it's worth about 5 cents.
The only "silver" penny was minted in 1943 to support the war effort. Yours is probably zinc plated.
They have never contained silver. Yours is probably silver plated for jewelry.