The car's Owner pays for all the fuel that goes into the car. They are then reimbursed for every kilometre the Borrowers drive through their chosen distance income.
Borrowers pay for the fuel they use through the distance charge.
Whoever is driving the car needs to make sure they leave it with at least a quarter tank of fuel - whether that's the car Owner or a Borrower.
If a Borrower needs to fill up during their trip, they pay with their own money and upload a receipt for reimbursement. The amount they spent on fuel will be deducted from the final charge for the trip.
Any fuel the Borrower purchases during a trip is charged to the Owner in their monthly invoice, and offset by the distance income.