What is the value of a 1979 Dollar Coin worth with a womans head on the front under the word liberty and an eagle on the back?

It's called a Susan B. Anthony dollar and it featured an image of the womens' rights advocate. Hundreds of millions were minted so they're only worth a dollar, even today except for a variety in 1979 which resulted from a design modification of the rim and is valued at about $10 in circulated grades and as much as $80 in mid range uncirculated grades.

The SBA dollar was an early attempt to make a small circulating dollar coin. Political interference kept it from being made with a distinctive design and metal composition, so the coin was constantly confused with quarters in change. Production stopped after 3 years. A second run was made in 1999 to supply transit agencies, etc. prior to the introduction of new gold-colored brass dollar coins.