Meet a pair of remarkable next-gen research tools: Casetext and Ravel.
Casetext provides the full text of cases for free accompanied by crowd-sourced annotations and links to secondary sources. Anyone can annotate the cases, and those annotations found most valuable can be up-voted. The site also has annotated contracts for those interested in insights from practitioners indicating which terms have fared best in court and other key pieces of information you might need as you draft agreements.
Ravel Law also provides the full text of cases for free, but its primary value is a visual representation indicating which cases are significant for the points of law you are researching.
Casetext is free, period. Ravel Law is free to law students; sign up with your .edu email address to get full access to all of the cases in the Ravel Law database.