Go pick up a copy of the guidebook The Big Island Revealed. I have found them to be quite honest in their appraisal of Big Island hotels and resorts. I am sure they list some things in your price range.

We usually stay at the Hapuna Beach Prince Resort in Kohala, but the best rate we get there is about $220/night, more than what you want to spend. However, if you are interested there is a recent report with pictures on the Trip Report board.