ChatGPT Plus is listed at $20, but the actual price you pay can vary from about...

https://romeo-wiki.win/index.php/What_Is_the_ChatGPT_Deep_Research_Limit_on_Plus%3F

ChatGPT Plus is listed at $20, but the actual price you pay can vary from about $13 to $27. This depends on things like VAT or GST taxes in your country or extra fees added by app stores on iOS and Android