At most destinations, you can save money by really shopping for rental cars. Disney seems to be a sellers' market for rental cars, and I was surprised how expensive cars were there when I checked prices recently, but if you are willing to do a little work, you might save.
I don't pay much attention to codes and "special discounts" with travel costs, because I've usually found they are discounts off the rack rate, but somewhat more expensive than I can get just by being a prudent consumer. Check them, but don't automatically accept them...especially on rental cars.
I start at one of the major travel sites like Expedia to do my initial shopping. There are two things you have to watch out for at those sites -- "Preferred" vendors" and the car description.
Most sites have preferred vendors, who are preferred only because they pay the site money to be preferred -- which means having their offers at the top of the list. But just because the site loves them to death doesn't mean they will give you the best price.
Fortunately, most sites give you the option to sort by price low-to-high. That is always my starting place.
Unfortunately, the lowest price is not always the lowest price because the car descriptions are just marketing ploys. What one company advertises as a "mid-size" might be a "compact" to other companies. So you not only have to check price, you have to check the actual cars offered to be sure you are doing an apples to apples comparison. One company's "midsize" may be a MUCH better value than another company's. Most sites have an option to show the actual car descriptions, and that is very helpful.
I also usually follow the travel site exercise by going to the rental car company's website to make the actual rental reservation. Two reasons: 1) I don't pay up front like I would have to on some travel sites, so I'm not in a jam if my plans change, and 2) I can sign up for the company's frequent renter program while I'm there. You should always sign up for that because it's free and saves you a lot of time standing in line when you pick your car up.
One other thing you have to REALLY watch in car rentals is extra fees if you are turning the car in somewhere different from where you picked it up. On a trip to CA a few years ago, I got a good rate from one company. But when I added in their "drop-off fee," it was costing me $200 more than another company who didn't charge any dropoff fee for picking up the car at LAX and turning it in at SFO.
Yes, rates do often go down as you get closer to your rental date.
