Premium tank sale - value in != value out

Dakiras: What you're proposing is a free rental service, which doesn't apply to even the real world. You rent a car, let's say you do so for €100. You drive it around for a bit and thus spend money on fuel (consumables) which you obviously don't look to get a return on... but then you take the car back to the rental garage and give it back to them. Do you then demand that they give you the money back that you paid for the rental?