The most readily available rental agencies on property are National/
Alamo (locations at the Dolphin and the Car Care Center). There's also a
Budget at the Doubletree, and an
Avis at the Hilton. When the Holiday Inn was a Courtyard by Marriott, there was a Dollar rental desk there. Not sure if it is/will be there when the Holiday Inn opens back up. Anyway - Hotel Plaza Boulevard is on Disney property just across from the Marketplace. It's very easy to get back to Downtown Disney if you drop a car off at one of these locations.
Before you decide to keep the car for a only a few days, just see what the rates are to keep it for your entire trip and just return it at the airport. Sometimes, there's specials that may get your total to be the same, lower, or only slightly higher than a 1 way rental.
As others have mentioned, your current auto insurance and/or credit card will most likely cover rental cars. Double check with your credit card, and/or your auto insurance carrier to find out about coverage.
Many times, if you sign up for a rental car agency's frequent renter program, it's free and you can completely bypass the line. I like National's Emerald Aisle. You can enroll
here for free.
Costs can vary greatly depending on agency, specials, length of stay, car class, etc.... Fr good advice on getting a good rate, check
here.
I've used Budget, L&M and National. I tend to stick with National because I love the Emerald Aisle. You reserve a midsize and can go to the midsize aisle and pick whichever car is on that aisle. Twice, I've been able to get a minivan for the cost of a midsize. I certainly don't depend on getting a crazy awesome upgrade like that, but when it happens, it's nice!
