Divide the class into teams of five. Each team will be assigned a different grocery store from a different chain. (An independent is fine.) Appoint a group leader. The group leaders should meet as a group and pick fifteen nationally branded grocery items. Each item should be specifically described as to brand name and size of the package. Each team will then proceed to its assigned store and collect price data on the fifteen items. The team should also gather price data on fifteen similar store brands and fifteen generics, if possible. Each team should present its results to the class and discuss why there are price variations between stores, national brands, store brands, and generics. 

As a next step, go back to your assigned store and share the overall results with the store manager. Bring back the manager's comments and share them with the class?