For the 3D printing work, I so far have not had to pay anything. When I originally sent the model over to that dept and explained what I was looking to do, I had asked for an estimate, and was told to pass the files along to the co-op working with them.
When I insisted that I really wanted to pay and skip any problems that might come up in future, the exact quote was, "from the accounting people, it's not worth it to try to charge."
I think that because the co-op is doing the work, and it's running during off hours, it's easier to chalk the prints up to training.