ChatGPT Plus lists at $20 a month, but the actual cost varies by country and...

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

ChatGPT Plus lists at $20 a month, but the actual cost varies by country and device because of taxes and fees. VAT or GST gets added depending on where you live. If you subscribe through an app store, expect a markup to cover their cut