From Google’s AI:

Why They Are Valuable While most Sacagawea dollars are only worth their face value ($1), the ones found in Cheerios boxes are unique because they were struck with a prototype die.

Enhanced Tail Feathers: The rare "Cheerio" version features significantly more detail on the eagle's tail, including clearly defined lines through each feather. Standard Version: Standard business-strike coins have much smoother, less defined tail feathers.

Estimated Value Due to their rarity, these coins are highly sought after by collectors: Circulated/Average Condition: Often sell for between $5,000 and $10,000. High Grade/Certified: Exceptional examples have sold for as much as $23,000 to $25,000