Go to Hotwire.com. It looks like you will be going to WDW around August 6. A search for that date in Orlando came up with a 2-star hotel (Comfort Inn, La Quinta, Days Inn) for $29/night, a 3-star hotel (Doubletree, Radisson, Holiday Inn) for $43/night and many more deals. I would probably go no lower than a 3-star hotel.
I used hotwire.com to get a deal on hotels on my last trip to Baltimore last month (to see 3 Red Sox games) . I was able to get 2 nights at a Holiday Inn for $59/night. The day before we had planned to drive down to Baltimore, I decided to go to Baltimore one day earlier, so I went to Priceline.com at 3:00pm and bid $50 and I got a room at the same Holiday Inn for that evening. We arrived at the hotel 7 hours later.
I was very satisfied with the accommodations that we had for a great price and I would not hesitate to use hotwire.com and/or priceline.com again.