Welcome Renee70 and congrats on your new job with Mono County!
Here are two classified ad websites you can peruse to try and find a place to live:
Mammoth Times
http://www.mammothtimes.com/content/classified-listingsThe Sheet
http://thesheetnews.com/free-online-classifieds/Fair warning that nothing is "cheap" in our resort town of Mammoth Lakes. You will most likely have a difficult time finding much to choose from now that the ski season has begun and many seasonal employees have moved in to town and are still arriving. It's best if you can come here for a few days and hit all the real estate offices and check out the "For Rent" or "Roommate Wanted" flyers at all the coffee shop bulletin boards around town, including the one at the Post Office.
Lots of luck to you!