I've been punching in all these codes for a MIA 3 day 12 hr rental.

I found that booking a flight + car with expedia gives me the cheapest rate --20/day + tons of taxes, but still comes in significantly lower than using all these codes.

Same thing happened when I rented in Boston a few months ago -- I saved $60 for a three day rental by booking the airfare and car together on expedia. Happily, the flights were with AA so while I paid $5 more for the tickets for booking on expedia (rather than directly with AA) it still saved me a lot of money.

If anyone knows of a better code to try for Florida, please let me know?