The 40% silver versions of the Bicentennial Quarter, especially those in uncirculated or proof condition, are more valuable than the more common copper-nickel clad versions, but their value is usually under $50.
Bicentennial Quarters in exceptionally high grades (like MS-70) might be valued higher but generally only reach a few hundred dollars at most.
Coins with minting errors can be more valuable, depending on the rarity and nature of the error. However, even the most sought-after error coins typically do not exceed a few thousand dollars in value.
Quarters that were part of special mint sets or first strikes might carry a premium over standard circulation coins.