I just subscribed to Pro Plus, I have a question about how credits work.

Hi, I just subscribed to Pro Plus plan and started to use desktop IDE, I read that Pro Plus gives me 500 requests a month, 5 minutes ago I used IDE and sent one request, a simple task, but I see credits consumed $1.4 quickly on my account webpage, can you please explain how does it work? Will I get 499 more requests? Or is it calculated based on credits? I subscribed because I wanted it based on requests not credits, any answer will be appreciated.