I also generally tend to find the best prices with my AAA code. I am frustrated with having to go through each rate special on the website to see whether it results in a lower rate (I guess I could go through all of the applicable specials and write down each code and then change the code on the How screens). I wish there were a way to list the rates for the applicable specials on one screen.

Also, if the special rate is sold out or you didn't meet the requirements, there is a short error message telling you the promo code has been removed and pricing it without any code but not really explaining why (it need to have a detailed explanation such as "use of that code requires a Saturday night stay" or "that location is sold out of cars for that promo code for your rental dates, but other sizes are available and are listed below"). This is also a frustration for me with Hertz's site, so watch for the message as you are trying different codes.