Below are guideline(s) to Disallow User to View Item Cost / Selling Price :

Step 1 : Go to System >> Security Manager >> User Profile Management

Step 2 : Select user ID from “List”

Step 3 : Untick “Allow show cost on item listing” or “Allow show standard selling price on item listing”

Step 4 : Click “Update”

Item Cost / Selling Price will be hidden from user