ChatGPT Plus starts at $20 a month, but what you actually pay can vary...

https://research-wiki.win/index.php/Why_Is_ChatGPT_Plus_More_Expensive_on_iPhone_Than_on_the_Web%3F

ChatGPT Plus starts at $20 a month, but what you actually pay can vary depending on where you live and what device you use. That price includes taxes like VAT or GST, which differ by country