[franga2000]

Here it's around 8€ per unit for national ILL and 17-38€ for international (depends on the system it goes through and may be even higher in special cases). You can also get copies of articles for a bit less, but that's not always available.

None of that is unreasonably expensive, but I can see it adding up quickly if you need to order like half of the things in your references (which might happen if your institution isn't subscribed to one of the bigger journals in your field).