@toreishi I think it is totally OKAY for Sitters who have been invited to sit to say, “Since the RT flight would cost $450, and car rental would cost $1200, it is not worth it to me, to travel and take care of your home and pets. If you could allow me to use your car while I am there, I would consider doing it.”
In this situation, the invited Sitter is not asking for money, and they are not asking for travel expenses. They are simply asking if use of the Owner’s car is a possibility, since otherwise, they cannot do the Sit.