ChatGPT Plus is listed at $20, but the actual price you pay can range from $13...

https://atomic-wiki.win/index.php/ChatGPT_Plus_Deep_Research_Not_Working:_Did_I_Hit_the_10_Per_Month_Cap%3F

ChatGPT Plus is listed at $20, but the actual price you pay can range from $13 to $27. Differences come from factors like taxes (VAT or GST) and extra fees from app stores like Apple or Google