Most sites offering business cases require you to purchase what you want. There are some library resources that can give you access to cases, however. When searching the following databases, try search for a topic and add the phrase "case study."
EXAMPLE: Amazon and "case study"
EXAMPLE: ethics and case study.
All materials in these databases are free for your use.
There are some open access business case sources available online. You can try searching one of these sources: