What is a 1940 error penny with D instead of 0 worth?

A 1940 error penny featuring a "D" instead of a "0" can be quite valuable to collectors, depending on its condition and authenticity. Typically, error coins can range from a few hundred to several thousand dollars, particularly if they are graded highly. However, the specific worth can vary widely based on market demand and the rarity of the error. Consulting a numismatic expert or recent auction results can provide a more accurate valuation.