There were no official prices on the twitter pages for the search endpoints and the powertrack apis. I tried to inquire and that is when I found out about the pricing changes (I am @blackforestboi on Twitter).
There were some prices mentioned about the Account Activity API which were also quite pricey already. I think something like $2500 to follow updates of 500 accounts or so.
The key difference is that most APIs consumers and projects used were the v1.1 and v2 apis which were free to use with rate limits that were actually quite generous.
(tweets, timelines, messages, bookmarks, lists, followers etc)
Now those APIs are all behind that enterprise paywall with that entry price of $42.000
$99/mo. for 100 requests, $1,899/mo. for 2,500 requests.
> 1 request is 30 days worth of tweets, or 500 tweets, whichever is first