Honest answer first: a circulated 2001-D is worth $1, and brilliant uncirculated examples $2–$6 (USA Coin Book). The top of the census is thin — MS68 examples list around $390 with an auction record of $546 (Greysheet, PCGS) — but that's a certified-registry game.
The reason to look closely at any golden dollar: the series hides some of the most valuable moderns in existence — the 2000-P “Cheerios” prototype reverse (thousands of dollars), the 2000-P Wounded Eagle (hundreds), and the Sacagawea/quarter mule that sold for $194,062 (CoinWeek).
Learn what to check in our rare Sacagawea dollar guide or browse our Sacagawea dollar collection.
Been wanting to get a full set of these coins in order to have a piece of history. Beautiful design. Very nice coin.