Junk silver (previously circulated coins) can be purchased at the daily silver spot price. There is usually a different premium (markup) for rounds/bars vs eagles. I've been to a shop where 1 oz silver rounds/bars were a dollar more spot value.
Silver Coin Melt Values with Live Silver Prices - Coinflation
I've never been in a shop or on a website where pre-1964 coins were sold at the spot price for their silver content without some level of markup. Where are you buying at spot price??!!??