Cases, codes, and regulations are Primary sources. You can usually access a free version of cases and codes through government resources such as Congress.gov, Regulations.gov, or FDsys. You can also access them through a subscription database such as Nexis Uni. Nexis Uni has "added value" information such as annotations, summaries, headnotes, and notes on case treatment to understand and further navigate legal information. I typically use the United States Code and Code of Federal Regulations through the FDsys (it is browsable) and Lexis Uni for news and law review articles.
Executive Branch Agencies