Originally Posted by
getagb
I agree, I'd almost never do it. But I think it makes sense in this case: I have a prepaid rental for $155, and I have an amex offer for $40 off $200, so even if the prepaid gas is a bit pricier I don't think it will be $40 pricier.
Is the Amex offer for a single purchase of $200, or multiple totaling $200? I don't think you can prepay for fuel at the time of reservation - how will they know the tank size if the vehicle is not yet assigned, not to mention the daily fuel price? If you pay $155 at booking and $50 for fuel at pickup as two charges it will not trigger a "single $200 purchase" Amex offer. Read the fine print.