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

https://fun-wiki.win/index.php/Can_I_Avoid_VAT_on_ChatGPT_Plus_with_a_VAT_ID%3F

ChatGPT Plus is listed at $20 per month, but the actual price you pay can vary between $13 and $27 depending on your location and payment method. This happens because taxes like VAT or GST and app store fees get added on top