You might want to visit the rent/trade board on this site. You can get a deluxe resort for the same, or even less than, a budget on-site resort by renting Disney Vacation Club points from a DVC member who can't us them. If you have a large crew of kids, the extra space of a 1 or 2 BR is a blessing, and might cost less than 2 rooms. If staying off-site, you might also try time-shares or vacation home rentals. These are typically rented out to the general public when owners aren't using them. You can often get a really great price.
DH and I own both DVC and Hilton Grand Vacation Club. Hilton has 2 resorts close to WDW, and both are beautiful. Vistana is another great resort nearby. They often rent out their condo-like accomodations to the public. I have seen 2BR for as little as $120/night. If you are really looking cheap, Comfort Inn has several around the WDW area that can be less than $50/night. Stay away from Budget Inn and Econolodge. We have stayed at these places on our night of arrival and have had really bad experiences with both chains. Dirty bed sheets, vomiting drunk guys, sticky stuff on the floor, that kind of bad experiences.
Good luck with your choices.