Beware: If you had already prepaid a rental with an online travel agency, don't let them talk you into an upgrade "...that's less than your prepay..." cuz it's an additional cost on top of what you already prepaid. They don't tell you it's an additional cost. They make it seem like they are doing you a favor because the price of the upgrade was lower or on special pricing than your prepay. It's not a discount from your prepay, it's an additional cost.
