Thanks for the info! I think implementing both an usage based version for example on the API access and a flat fee for let's say the webapp can be a way to go,

Thanks for the info! I think implementing both an usage based version for example on the API access and a flat fee for let's say the webapp can be a way to go, to increase flexibility, but is a personal opinion. I like Perplexity model which is like that, I can use the webapp for daily quick searches and use the API for more programmatical access with a more granular price control. Of course then is up to you, anyway I find this to be a great way to do it.