Florida Car Rental Discounts most providers!
There are several really good car rental coupons and discounts specifically for Florida. Many of these can save you up to 75% off base rates. Discounts can vary by code and time of year.

Avis:

AWD - K199060 - Gives really good discounts on most car classes. Is from a Florida tourism organization and can be used by anyone.

Dollar/Thrifty:

These codes also give really good discounts on most car classes.

Dollar - corporate code oi1054

Thrifty - Thrifty Corporate code 004M001010

These require a copy of the Free Orlando Magicard - link : http://www.orlandoinfo.com/magicard/download.cfm

I found these coupons at: http://www.carrentalsavers.com/florida-car-rental.html

Budget:

Use Budget BCD: Y937800 for up to 15% off in Florida.

This came courtesy of the Disboards - http://www.disboards.com/

Alamo:

Use contract ID: SUNPROMO for 15% off in Florda. Must pickup by 12/15/09.
Use contract ID: 7014667 for 10% off in Florida. Must pickup by 12/15/09.

These came from Alamo emails. Have not had much luck with these though. You may be better off using other contract ID's. Worth trying though. You can also try the IG contract ID for last minute specials.

All codes are currently ongoing unless stated. Alamo, Avis and Budget codes can be combined with coupons.

thanks goodnessgraciou

Just ran a test for a trip in early March to Palm Beach. The Thrifty rate is a little higher than my corporate rate; difference is that mine gives 150 free miles per day, which is usually more than enough, while the Disney is unlimited. Also tried the Avis rate, which was not much different than AAA.

Great posting. I made my reservation already with Avis
Thanks OP

Try the carrentalsavers link. It seems to work there.