The listed ChatGPT Plus price is $20 per month, but the actual charge can vary...

https://www.protopage.com/haleymartinez95#Bookmarks

The listed ChatGPT Plus price is $20 per month, but the actual charge can vary from about $13 to $27 depending on where you subscribe. This happens because taxes like VAT or GST and extra fees added by app stores affect the final cost