I just did a quick check on the Disney website for 12/7-12/13. All of the value resorts are showing for under $130 a night. Easily doable for that $80 a person and able to stay on Disney property. And that's paying the posted rates on the Disney website.
The Hilton LBV across from downtown Disney is available @ $112 a night on the MVP site. The Embassy Suites LBV is even cheaper.
So there are plenty of rooms available for way under your budget. I think you just need to do some actual research and pick a place.