I can highly recommended FULL MOON RESORT. Nice facilities, not too large, right on the beach. Centrally located and surrounded by great restaurants (Local Food is great, even for the not to adventurous)
Some of the staff are excellent and speak decent english while some others are downright surly. Prices start at US$20 to $60 incl Breakfast. Sure there are cheaper places around, but I had a blast there. All ready planning to return next Feb.
Look at this link for further info. It hasn't been updated for a while, but has links to most of the accom in Mui Ne
www.adambray.com