The Harrah's group of resorts is offering some deep discounts on rooms in December. Some rates were as low as $32/night. The Harrah group includes Harrah's (obviously), Caesars Palace, the Flamingo, Bally's, Paris, the Imperial Palace and the Rio. Go to
https://www.harrahs.com/hot-deals/ and choose Las Vegas from the "Select a Destination" drop down list. Change the "Calendar Options" on the subsequent page to the dates your interested in.
Edit: I just did a search for December and the $32 rate was for Imperial Palace which is a dive but they were offering $70 at the Flamingo and $79 at Paris for the same nights. Paris is a pretty decent place with a great location on the Strip.