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.
General
Executive Branch Agencies
Congressional Committees