What is the value of a Sacagawea dollar with no date?

Take a good look to make sure the the date has not been removed by grinding or polishing. If it hasn't this is likely caused by grease filling the date on the die resulting in the date not striking up. This very common an some people do collect this stuff, take it to a coin show or dealer for a value.

Or you may have a new oneIf the back of the coin has a picture of a Native American woman planting grain, you have a 2009 dollar. The date is on the edge of the coin, the same as on the Presidential $1 coins.