The 2008-S Proof Sacagawea Dollar is the lowest mintage proof dollar in the series from 2000- 2008. It is also the last year in which the Mint struck Sacagawea dollars with the eagle reverse design. As the following year or in 2009, the Mint began the Native American Dollar series which changed the reverse design of the dollar coins.
Most 2008-S Proof Sacagawea Dollars were struck almost to perfection but not quite, since most coins still grade PR69 or lower. Raw or PR69 or lower condition coins can be purchased very easily without a significant premium. Perfect PR70 coins usually command a higher premium but not too high since there are enough perfect coins to meet the demand.