The listed price for ChatGPT Plus is $20 a month, but the actual cost you pay...

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

The listed price for ChatGPT Plus is $20 a month, but the actual cost you pay can range 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