One of the more interesting points of discussion was that when big companies negotiate purchase agreements for parts, the actual cost of the parts can be very transparent. The negotiation is generally about the actual markup e.g. "I think we should pay X% over cost.
Someone, logically, brought up: "What if the company is not willing to share the cost upfront?".
The professor responded: "Well, if it's a public company you can generally deduce a rough cost/part and use that as your starting point in the negotiation"
Student: "Well what if the company says we're wrong?"
Professor: "No problem: ask them what the correct number is. If they don't want to give it to you, ask them how you expect to have a long term partnership if you are not willing to talk openly and honestly about things like parts costs."