Your $3.91 fuel is the equivalent of $0.25 per gal. if you were using 1964 silver coins. In 1965, they took the silver out of dimes, quarters and half dollars. The new sandwich coins have no precious metal content. Some years back I put about 5% of my investments into gold and silver coins. Now it has grown to be about 7% of my total so it has beaten the stock market.