The claim that a single rare Bicentennial Quarter is worth nearly $450,000, with three more worth over $100,000 each, is highly unlikely and would be considered extraordinary in the world of coin collecting.
Bicentennial Quarters, as previously mentioned, were minted in large quantities to commemorate the 200th anniversary of the United States and are not typically considered rare or valuable.
While it's possible for certain rare coins to fetch high prices among collectors, valuations in the hundreds of thousands of dollars for individual coins, especially common ones like Bicentennial Quarters, are exceedingly rare.
If such valuations were accurate, it would likely be due to extremely unique circumstances such as a major error, historical significance, or some other exceptional attribute.
However, without specific details about the rarity or uniqueness of these coins, it's challenging to assess their true value.
If you believe you have rare coins that may be valuable, it's advisable to seek a professional appraisal from a reputable numismatist or coin dealer who can provide an accurate assessment based on factors such as rarity, condition, and demand among collectors.