How much is 1988 20 bill with star on it?

A 1988 $20 bill with a star (indicating it is a replacement note) can vary in value based on its condition and demand among collectors. Generally, if in good condition, it may be worth a premium over its face value, typically ranging from $30 to $100 or more. For an accurate assessment, it's best to consult a currency collector or a grading service.