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

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

ChatGPT Plus is listed at $20 per month, but the actual price you pay can range from about $13 to $27 depending on where you subscribe. This difference is mainly due to taxes like VAT or GST and fees added by app stores on iOS or Android