1971 Kennedy Half Dollar Value is .50C to .75C in circulated condition, and uncirculated examples can bring $1 to $3 raw.
1971 Kennedy halves can be worth $30 in MS65 and $110 in MS66, if graded by PCGS or NGC.
These are not silver but copper nickel and clad and they where minted with D (Denver Mint) mint mark or without a mint mark (Philadelphia Mint) for 1971-1979.
Copper-Nickel Clad Coinage (1971-Date)
Obverse by Gilroy Roberts; reverse by Frank Gasparro
Diameter: 31 millimeters
Metal content:Outer layers – 75% Copper, 25% Nickel
Center – 100% Copper
Weight: 175 grains (11.3 grams)
Mint mark: “S” (Denver Mint) and centered above the date. It is normal for 1971 through 1979 to be without a mint mark.