Look, coins have as much value as wither "you" apply to them or what "you" can sell them for. No two MS65 1971-D Kennedy Half's have the same value and adding or applying a "blanket" value such as certain "price guides" is just a fools chase. In a nut shell, any Kennedy Half Dollar produced from 1971 up to today has a value of 50 cents "unless" the possessor or owner of the coin can find some added value and sell the coin as such. I've paid more than 50 cents for coins which were either advertised as varieties or error coins. I've submitted these coin and theoretically, increased their value. To the non-specialist, these coins are worth: 50 cents. It's all about what you know.