Don't count out Priceline. September is still the "hot" season and I have had great luck getting very nice (4 star) hotels in the great PHX area (I prefer Scottsdale/Paradise Valley but there are tons of other areas) for way under $100. My lowest ever (again, for very nice 4-star resorts) were $58 and $65 a night during hot season.
Good luck.
SEA2BA