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

https://suprmind.ai/hub/chatgpt/pricing/chatgpt-plus-price/

ChatGPT Plus is listed at $20 per month, but the actual price you pay often varies between $13 and $27. This happens because taxes like VAT or GST and extra charges from app stores can add to the cost