The claim that a Bicentennial Quarter is worth over $90 million is highly dubious.
Bicentennial Quarters, which were minted in 1975 and 1976 to commemorate the 200th anniversary of the United States, are relatively common and not typically considered rare or valuable.
While some Bicentennial Quarters may have minor variations or errors that make them more desirable to collectors, it's extremely unlikely that any single Bicentennial Quarter would be worth anywhere near $90 million.
Valuations of rare coins are typically based on factors such as rarity, condition, demand among collectors, and historical significance.
While there are certainly coins that can command high prices in the collector's market, values in the millions are exceedingly rare and usually reserved for coins with unique historical significance or extreme rarity.
If you have a coin that you believe may be valuable, it's always best to consult with a professional numismatist or coin dealer who can provide an accurate appraisal based on current market conditions and the specific attributes of the coin in question.