The 2006-D Sacagawea Dollar carries the same design used since the year 2000 - 2008.
In uncirculated grades it is easily obtainable for a small premium. Only in high grades does it become challenging to find.
MS60 - MS65: In Uncirculated grades up to MS65 they can be allocated very easily. there are many raw examples still available that sell at a very small premium.
MS66: In MS66 condition it is out there but it does require some searching to find.
MS67: Requires lots of searching and it might just make more sense to buy a graded example, since the odds of finding a raw example in this grade are almost unlikely.
MS68: in Ms68 condition they are very scarce with less than handful discovered in this condition. Finding one in MS68 condition or higher would be a great find.