ClarabelleCow - If you want to get a really good rate and are staying on Disney property and you do have access to Magical Express to at least get you to your resort..I found it cheaper to book at some of the rental places off site and got better rates.
I just booked Dollar rent a car out of the Regal Sun Resort right by Saratoga on Hotel plaza Blvd, and got a rate of $49 per day for a mini van using my Bj's corporate code - 'BJ3013'...feel free to use it. It was $35 cheaper than anywhere else I looked..and I was searching orignially on a mid size car. Again not sure where you are staying..but thought this was worth a shot. Good luck.