when booking reservations, try every single discount code you have, then call the location directly.

I have been able to beat my best reservation price by $5 per day by NOT using my reservation and just walking up. Airport locations will "rate shop" amongst competitors and try like hell to be competitive with each other. So you can go from one counter to another counter with your prices and you can beat them on occasion. dont EVER take for granted that the rates will be more expensive if you walk up. Thats the normal situation, but far from the rule.

If your reservation is better, then use your reservation. if your reservation isn't the best, then use the walk up rate. When they find your reservation in the computer, just say "cancell that reservation for me will you?"

This is one of the main reasons i do not "pre pay" for my car travel. If I prepay, im locked into those rates.