What is the lowest price of a barrel of oil ever been?

Lowest price of a barrel of oil ever been in modern history was negative in 2020, which was unprecedented. On April 20, 2020, WTI crude futures for May delivery settled at negative 37.63 dollars per barrel, meaning sellers had to pay buyers to take oil, due to COVID pandemic demand collapse, storage tanks full, and futures expiration. This was lowest ever nominal price, negative. Before that, lowest positive prices were very low in early days, oil was about 1 to 2 dollars per barrel in 1930s during Great Depression and East Texas oversupply. In 1998, oil fell to about 10 to 11 dollars per barrel during Asian financial crisis. In 1986, oil fell to about 10 dollars. Adjusting for inflation, cheapest oil ever was in 1930s at few cents per barrel in today's dollars. So in recent decades, lowest was negative 37 dollars in April 2020, lowest positive was about 10 dollars in 1998 and 1986. If you exclude 2020 anomaly as futures quirk, lowest regular price was around 10 dollars. So answer is negative 37 dollars on April 20, 2020 is lowest ever, otherwise about 10 dollars.