I know at one time there was a small discount for being a DVC member when renting from this company. The code was was listed under the benefits section.
We rented through Magic Stroller in August and got a $5 DVC discount. Not sure if this is typical, but our stroller was very beat up and old. We've had better luck with Baby Wheels and get a 10% returning customer discount, but we went with Magic this time because they delivered to the resort without us having to meet them. That seems to be changing, however.
Remember that Disney has changed the rules for having this type of item delivered to your resort. WDW's preferred provided for strollers is Scooter Bug if you want the stroller dropped off and picked up without you personally being present at time of delivery and pickup. The web site is scooterbug.com/Orlando and the phone number is 1-800-726-8284.
You can still rent from other venders but you have to be present to accept delivery and for them to pickup the scooter at the end of your trip. There is another company located at the airport around the Magical Express area called Orlando Stroller Rentals the phone number is 800-281-0884. Good luck with whatever you decide.