You can use comps to negotiate a better house price by discovering what is deficient about your target house compared with the comps, and telling the seller and your realtor when you make your offer. You might say, “We are offering $5,000 less than your sales price because all the comps had central air conditioning, and this one doesn’t.” If the seller is motivated to sell, he may accept your offer, and reduce the sales price. Comps are usually provided by each client’s realtor.