Someone looked it up in a previous thread a week or so ago. IIRC, the PACER system had ~80-90 million in revenues, and $25 million in costs last year. I remember the discussion mentioning that all of the extra cash goes towards making up for a lack of proper budget from Congress for running the court system. It's a complicated issue.

Edit:

Looked up the posts:

https://qht.co/item?id=5053611

https://qht.co/item?id=5053483