What is the value of a 1975 - 1976 half dollar?

Answer 1

I'm not sure what you mean "1975-1976 half dollar". Half dollars (and "silver" dollars and quarters) minted around the bicentennial had a "date" of 1776-1976 imprinted on them. These coins were struck in both 1975 and 1976; none of these coins were minted with a date mark of 1975.

Assuming you mean the bicentennial half: it's worth 50 cents. (Don't believe me? Take it to a coin dealer and try to sell it.) Over half a billion were minted, and most went straight into sock drawers or the equivalent. (It's estimated that as much as a third of the quarters were effectively removed from circulation immediately by hoarders, and the figure is likely even higher for halves.)

They're unbelievably common because people think they're "rare" and hoard them. This has the paradoxical effect of making them not at all rare.