To Update:
So far going through Costco is best.
Budget was $575 including all taxes for 15 days.
Avis was $600. Both for a full size. These were about $440--$460 before taxes/fees. We will not need extra insurance, etc as we are covered with our home policy and we have a portable GPS.
Budget fluctuates wildly from day to day, even log in to log in for me? Like $300 up and down!
There are other coupons on the side that seem to save $20-$30 off the Costco rate. I got them to work for Budget.... But Avis' coupon had to be used by Dec 31, 2013? The rental had to be used by that date, so code would not apply. The click through windows for the coupons are right on the side of the screen so no need to key in a code, it does it automatically.
I will check both next week and probably reserve with no deposit. You only save about $20 to prepay, so will wait for better deals if they come out.
I will keep checking and hope it comes down closer to, but if it does not, I can live with this! So much better than the $800-$900 before taxes I was seeing everywhere!