Google Scholar provides a simple and free way to search for cases. The "cited by" feature can lead you to other cases, which can help you with your research.
Google Scholar offers a Help section as well as Advanced Search Tips. Both of these are invaluable for coming up with useful search terms so that you can find the articles you need.
By typing in the citation for a case on Google Scholar, you will get not only the case, but a list of the number of cases or articles that cited that case, how that case was cited, and any related articles to your case.