ChatGPT Plus lists at $20 per month, but the actual price you pay can range...

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

ChatGPT Plus lists at $20 per month, but the actual price you pay can range from about $13 to $27. This depends on factors like sales taxes (VAT or GST) and extra fees charged by app stores