When you login with the Developer account it gives you an option to upgrade and there you can see the prices. But I'll save you that: 2500 requests against their Full Archive costs 1899 USD. That's 75 cents per request.

That sounds absurd to me. 2500 requests is nothing and what if you're testing? The sandbox level is 50 requests for free.

Maybe I don't understand well the use cases but all the things that come to my mind for these APIs would required more than 2500 requests to do something interesting. They are pricing their data like if it was some sort of unique canonical truth vault when in reality 95% of it, it's just a bunch of shitposts.