ChatGPT Plus is listed at $20, but the actual price you pay can range from...

https://highstylife.com/i-keep-hitting-chatgpt-limits-should-i-start-a-new-thread/

ChatGPT Plus is listed at $20, but the actual price you pay can range from about $13 to $27. This happens due to taxes like VAT or GST and extra fees charged by app stores on iOS and Android