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

https://www.bright-bookmarks.win/the-listed-chatgpt-plus-price-is-20-but-the-actual-cost-often-varies-between

ChatGPT Plus is listed at $20 a month, but the actual price you pay can vary from about $13 to $27. This difference comes from added taxes like VAT or GST and extra fees from app stores like Apple or Google