Professors can sign up for a free Premium Educator account. Once a professor is signed up, he/she can create a coursepack. Normally, students are charged $8.95 for a case study, but if a professor registers for an account, the cost per student per case study is $4.25. If you have further questions, please refer to the Harvard Business Publishing for Educators website.
Case Centre is a website dedicated to free business case studies from institutions such as MIT and Stanford. You will need to create an educator account in order to access the studies.