RECAP is an independent project to collect federal court filings and make them available for free. Anyone who uses PACER can install the RECAP extension in their Firefox browser. With RECAP installed, Firefox will automatically make a copy of any court filing purchased on PACER and place that free copy in an internet archive where anyone can access it. To access filings on RECAP, you can either:
http://archive.recapthelaw.org/
There is a basic search and “advanced” search function at the RECAP archive, but the search capability is rather rudimentary.
Also, keep in mind that the documents available there are quite limited. They tend to include the more publicly notable cases, rather than run-of-the-mill litigation.