The bill you have is a German Rentenmark issued by the Rentenbank in 1937. While it is a historical currency, its cash value is generally negligible today, as the Rentenmark was replaced by the Deutsche Mark in 1948. Collectors might value it based on its historical significance and condition, so it could have some collectible value. To determine an accurate worth, consider consulting a currency collector or an appraiser familiar with historical banknotes.