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

https://wool-wiki.win/index.php/Why_Can_the_Same_ChatGPT_Account_Have_Three_Different_Prices%3F

ChatGPT Plus lists at $20 per month, but the actual price you pay can range from about $13 to $27. This difference comes from added taxes like VAT or GST and extra fees charged by app stores such as Apple’s or Google’s