None of these public databases is free. It is very expensive to create and maintain good databases and people who use them are asked to help pay for them, even if all taxpayers contribute most of the money to support these databases.
Online databases, of any kind, are not free or even cheaper than paper files – they just allow greater access, at a cost. The price of remote access is high since you need skilled and experienced programmers and designers and network specialists who can build databases that everyone can use – not to mention the skills, hardware, and software that are needed to keep a database secure and properly backed up – and have 24/7 user support. These skilled workers cost a whole lot more than people who sort and file paper documents.
There are also private, commercial, court document services where you can find case files online. These databases, however, are even more expensive than OJIN or PACER. Big law firms, many with law librarians and other expert database searchers, will subscribe to these, but here too as with anything we buy or sell, the costs are passed along to the people who use them, the client or customer.