Can change Price of Catalog Item

Summary

When selecting an item from the catalog and the item is from an active BPA, once in the cart the user can change the cost.

Content

When selecting an item from the catalog and the item is from an active BPA, once in the cart the user can change the cost. How do I stop this so the user does not change a $100.00 item to $0.01 for approval and the sent to the Supplier with the wrong price.