How much is a 2003 S quarter worth?

The value of a 2003 S quarter, which is a proof coin, typically ranges from $2 to $5, depending on its condition and whether it has been graded. If it is part of a complete proof set, its value may be higher. However, in general circulation, it would be worth face value, which is 25 cents. Always consider checking with a coin dealer for the most accurate valuation.