The value of a 1964-1970 half dollar depends on its condition and mint mark. In general, these half dollars are worth around $1.00 to $2.00 in circulated condition. Kennedy half dollars minted in 1964 were not marked, but half dollars minted from 1965 through 1970 have the mint marks D (Denver), S (San Francisco), or no mark (Philadelphia). However, some half dollars from this era can be worth more, especially if they are in uncirculated condition or if they have errors or special features. For example, the 1964 Kennedy half dollar with no mint mark is considered a key date and is worth around $10.00 to $12.00 in uncirculated condition. The 1968-S Kennedy half dollar is another key date and is worth around $5.00 in uncirculated condition. Half dollars from 1969 and 1970 are not as valuable, but they can still be worth a few dollars in uncirculated condition. If you have any 1964-1970 half dollars, you should take them to a coin dealer or appraiser to determine their exact value.