That would depend on the country of the coinage.
500
HALF a dollar - $0.50
It's worth 50 cents.
No such coin exists
The British currency has never included cents.
The 1915 Eagle is a common Philadelphia Mint issue coin and assuming it's circulated and in collectible condition average values are $800.00-$925.00.
The Bicentennial Half Dollar is worth from $2-5
Unless the coin has an "S" mintmark, such a coin is only worth $.50 because it is extremely common.
The coin is still in circulation and is face value.
The coin is still in circulation today and has face value only.
If the coin has any wear the value is for the silver about $12.00
$9 to $35,000 depending upon the mint mark and the condition of the coin.