You must be talking about ChatGPT Plus? The GPT-3 API is pretty cheap in my experience
$20 a month isn't that bad for Googles alternative.
I've heard Microsoft are pushing a $40 a week access to the same tool. I imagine it will be token limited though.
> Duolingo
They're already using gpt3 afaik
Curious to know what part of the app they're using it for. I haven't used duolingo in the last 6 months.