99 pence
it is around a dollar, over 9 million were minted so they are not that rare
None, such crowns are all copper-nickel and run about $1 in uncirculated condition.
The 1965 'Churchill' Crown was mass produced in 1965. 19,640,000 were struck in cupro-nickel (an alloy of copper and nickel). They are worth today (September 2010) between 50p and £1 depending on condition.
You are probably referring to the 1965 commemorative Crown (a denomination equal to 5 shillings, or a quarter of a British pound) issued in Great Britain. The coin is larger and thicker than a US silver dollar, and there is a portrait of Queen Elizabeth the Second on the front, and a portrait of Winston Churchill on the back. It is worth about a dollar in circulated condition.
It's not a US half dollar; it's a crown (or 1/4 pound or 25 pence) coin from Great Britain. It's worth less than a US in circulated condition, and perhaps US$1 or US$2 in Uncirculated.
£200
Winston Churchill featured on the reverse of the 1965 British Crown, commemorating his death.
Such a coin does not exist. The "Churchill" Crown was a Five Shilling coin issued in 1965. The 1977 Crown was a 25 Pence coin commemorating the Silver Jubilee of Queen Elizabeth II.
Try eBay or a reputable coin dealer. They do not have all that much value , so do not go to too much trouble. British 1965 Crown - Churchill commemorative.
It's worth exactly one pound.
The last British Crown (5 Shillings) coin to be minted was the 1965 Churchill Commemorative.