Consider Hotwire.com.
Have used them for 12 years, booked 24 hotel stays and saved $1833.00
Usually choose 3-stars and up.
Un-sold rooms?
I have really saved big $$ on same-day arrival, typically booking from from a McDonalds in the town, via free wi-fi, then drive to hotel and check-in.
Leaves all other corporate plans, discounts in the dust!
Helpful site: