No US quarters dated 1966 are silver. The only US quarters struck in silver are dated 1964 or before with the exception of silver proof sets (most proof sets are -not- silver and silver proof sets are marked as silver) but those are dated from 1992-present.
If you mean a 1966 American quarter, then none.
All of the quarters struck for circulation from 1965 to date, have NO silver and are just quarters.
$50
It's a common date, worth at least $3 for the silver and up to $5 in good condition.
$3.00
A quarter from 2006 would still be worth 25 cents.
Twenty five cents each. Silver-plating adds no value.
$10
it is worth about 50 dollars
Around $6.
1964 was the last year for silver quarters.
The value is only for the silver about $3.25