Open Question: Where to buy music cd's/records/cassttes in bulk to sell in a music store?

I am doing a project for school where we have to design a business and we have to find all the details. Like where to buy the products that we will be selling. And i cannot seem to find a place that sells cd's/records/cassettes that i can use. Can anyone help? I am junior in high school and this is a project for one of my business classes and i need to find this or i will lose major points