There is no guarantee with Priceline - most hotels will honor a request for a non-smoking room if they have non-smoking rooms available. It may be best to call the hotel now, so they can add your request to your reservation. You almost always get the star rating of a hotel that you bid - its possible to get a higher star rating (but not a lower star rating) if there are no hotels available at the start rating you bid, but there is a higher star rating at the price you bid.