US coins are 78% silver to face ratio, so just multiply your total face value times 78% and then multiply by the spot price of silver. That's the bullion value. Most dealers will give you 90% of that, the 10% is their profit. Dealers who will give you less than that should be avoided, as well as dealers who want to weigh the coins and avoid paying for the wear, which is minimal. They all sell at spot price plus, usually on face value, that's the basis.