The value of a 1991 Queen Elizabeth II 1 dollar coin can vary depending on its condition and other factors. In general, these coins are not considered rare or highly valuable. They are typically made of nickel or aluminum-bronze and have a relatively low intrinsic value.
In circulated condition, a 1991 Queen Elizabeth II 1 dollar coin would likely be worth its face value of 1 dollar. However, if the coin is in uncirculated or mint condition, it may have some collector value, albeit not significant.
To get a more accurate assessment of the value of your specific coin, I recommend consulting with a reputable coin dealer, checking online coin marketplaces, or referring to coin pricing guides. These sources can provide you with the most up-to-date information on the market value and potential collector's value of your coin.