Contact as many water-proofing companies as it takes until you are in agreement with their cost and work provided. You will not me sorry. The majority of my clients that see or smell a wet/on-going damp basement, rarely purchase those homes. If you are just trying to make the basement floor look fresh and clean, check with a local Home depot, or Lowe's type store and they should be able to guide you as to which product to use.
Best of luck,