Renae:
The most economical way to stay on Disney property for a family of 8 (unfortunately, you can count one of the twins in a crib, but not both) is to book two rooms at one of the Value Resorts. (Our family's favorite is All-Star Movies.) I would use this as the benchmark for your budget if you are looking at rooms off property or the Good Neighbor hotels which have decent prices on suites near the Downtown Disney area. Another option is to look into renting a vacation home (some even come with pools) from a business like All-Star Vacation Homes. Keep in mind that when you stay off property, you'll have to pay for parking for the theme parks, too, so keep that in consideration.
With free dining being offered next year for most stays on Disney property (click
here for more info), you may find that staying on property may actually be cheaper than staying off property. I have found that working with a Disney-certified travel agent rather than booking myself, is the best way to find out the offers--and Disney pays their commission. They will have information on both hotels on property and the nearby Good Neighbor hotels.
Lastly,
Downtown Disney is a shopping district on Disney property that also includes restaurants, DisneyQuest, a cirque show and free outdoor entertainment. One of our family's favorite endings to a trip is to visit the massive World of Disney store for any last-minute souvenirs and enjoy a stop at Ghirardelli's. On our last trip, we set off after lunch with the dinosaurs at T-Rex and had the best meal of our entire trip with the balsamic chicken flatbread and ravioli!
Wishing y'all a magical vacation!
Whitney