Here are some short notes on silver. Due to either lack of scarcity or wear it has no numismatic value as a rare coin. Quarters and then dimes are the most common with halves usually selling for a slight premium.
Silver dollars sell with a significant premium.
Now please note that bags of silver always cost a little more than this due to sales tax, transportation, dealer premium, etc. Below is a brief summary of information on metal coins. U.S. pennies were made of copper before 1982 with some made in 1982. Since copper is a non-precious metal you use avoirdupois, not troy measurement. This does NOT include the cost of melting, purifying, etc.