The listed price for ChatGPT Plus is $20, but the actual cost can vary from...

https://smoothdecorator.com/why-did-openai-keep-chatgpt-plus-at-20-since-february-2023/

The listed price for ChatGPT Plus is $20, but the actual cost can vary from about $13 to $27 depending on where you subscribe. This difference happens mainly because taxes like VAT or GST apply in some regions