ChatGPT Plus has a list price of $20, but the actual amount you pay often...

https://wiki-planet.win/index.php/Why_Do_My_Answers_Get_Worse_After_I_Hit_a_Limit_on_ChatGPT_Plus%3F

ChatGPT Plus has a list price of $20, but the actual amount you pay often ranges from about $13 to $27. This difference depends mostly on extra costs like VAT or GST taxes and additional fees from app stores like Apple or Google