I looked at Kayak - the cheapest rate (quoted as a daily rate) for the major car rental companies in Maui (for economy or compact cars) ranged from $41 to $44 day. As linked web site (discount Hawaii car rentals) quoted me for a similar type of cars at the base weekly rate of $140+.

Is this booking through one of the web sites, reliable? Are these the cheapest weekly rates that I can get? If not, through what mechanisms do I find cheaper weekly rates?