Currently, there's no way to automatically give a borrower a discount for your car. This is a feature we would like to build in the future, but for the time being this needs to be done manually.
Sometimes owners like to give discounts for long bookings or to regular borrowers of their cars. If you would like to do this, please send an email to email@example.com with the details of the booking and discount you would like to give. We can then process the discount manually for that booking.