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

https://rowansnewwords.tearosediner.net/why-does-chatgpt-plus-cost-more-than-20-for-me

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