Because of its high silver content, 1964 Quarters are worth far more than their face value (25c); in fact 16x more. The melt value for these coins currently sits at around $4.
However, 1964 D Half Dollars in perfect ... to give you an idea of the coin's value. Keep in mind that coin values fluctuate based on various factors, including market demand, overall condition ...
In the case of silver quarters minted between 1960 and 1964, they might be worth $10 or more because of the silver contained within the coins. Some silver quarters from 1965 are worth thousands ...