The 1964 Kennedy half dollar, "Accented Hair" variety
In 1964 the first Kennedy half dollars were produced. The design used for the first few weeks is now called the "Accented Hair" variety. The second design followed without the "Accented Hair".
The coins used for commerce (Business Strike) coins were produced in abundant quantity so most of them don't have much if any numismatic value. Coins in the upper end of the 70 point grading scale can bring over $1,000. The Proof coins are much more scarce and command a premium even in lower grades (e.g. PR63). High grade examples can bring $3,000 to $5,000.
Here are photos of both types of 1964 Kennedy half dollars. Both photos are of Proof coins:
Below is "Accented Hair" variety
Below is "Normal" (not Accented Hair) variety