I second the carrentalsavers and also wanted to mention, keep checking often. The first time I looked I booked the lowest available so that I had a reservation then I kept checking, morning/noon/night over and over. If I found something for less I would book that then once I received the confirmation I would cancel the previous one. I ended up getting the cost down about $40 from my initial reservation and I happened to find the lowest price at 11pm one night only to check again in the morning when I woke up and the price had gone back up significantly again. I just happened to catch it at the right moment. It can pay to keep checking!
