What this coin looks like (obverse, reverse, mint mark location, special features, etc.):
1999 D Susan B. Anthony (SBA) dollars were the first dollar coins produced since the 1981 dollar. Due to a growing demand for small dollar coins in mass transit - banks began running out of these coins for the first time and the US Mint was asked to replenish the supplies of the small dollar coin. Since the US Mint didn't have the authority to change the design - they stuck with the original Susan B. Anthony design until 2000 when the Sacagawea dollar design was authorized for production.
Coin valuation chart: Typical coin prices, values and worth per grade or condition - in USD