What are first day issue stamps worth Elvis Presley and Marilyn Monroe?

First day issue stamps featuring Elvis Presley and Marilyn Monroe can vary significantly in value based on factors such as condition, rarity, and demand among collectors. Generally, these stamps can range from a few dollars to several hundred dollars each. Special editions or those with unique features may command higher prices. For an accurate valuation, it's recommended to consult a stamp catalog or a professional appraiser.