FridayGPT is also not really open about the need for an API key on their landing page.
Only in the FAQ they mention it.
Seems a bit shady to me.
There are also other AI tools listed there. https://buyoncesoftware.com/?category=AI
As soon as the AI models run on an external server a buy once model does no longer work (or atleast not with an acceptable one time price). The constant server cost is just to high.