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

https://highstylife.com/i-keep-hitting-chatgpt-limits-should-i-start-a-new-thread/

ChatGPT Plus is listed at $20 a month, but the actual price can vary between about $13 and $27 depending on where you subscribe. This difference mostly comes from extra charges like VAT or GST and fees added by app stores on iOS or Android