ChatGPT Plus has a listed price of $20, but the actual cost you pay can vary...

https://dibz.me/blog/is-there-a-chatgpt-plus-free-trial-i-can-click-to-start-1223

ChatGPT Plus has a listed price of $20, but the actual cost you pay can vary from about $13 to $27. This difference happens because of taxes like VAT or GST and extra fees added by app stores on iOS and Android