I was just chatting with the AI bot and did 3 French lessons, it was really good, seemed to recognise my voice/accent perfectly. But then it said "she" was tired and needed to rest, but I could buy premium for infinite energy. I'd be tempted to do so, but it didn't say how much it would cost? I appreciate that it might tell me the cost if I click "yes please" but also, as I've linked my google account to sign in, I'm hesitant to do that with a website that I don't know incase it charges me immediately. I would recommend that you make this process clearer on your website, I imagine that many people will leave and never come back once they are asked to upgrade but not told the price! Before that, it was working very well. If I knew the cost of subscription, I'd be interested in using it regularly to practice conversation.