You have several ways to determine the value of a home. One way is an appraisal, created by a licensed proessional. It is a professional estimate of a property's market value, based on recent sales of comparable properties, in similar location, having similar square footage and construction quality. This service cost will vary idepending on the price of the home. On average, a professional appraisal costs about $300 for a $250,000 house. A comparative market analysis (CMA) is an informal estimate of market value performed by a real estate agent, based on similar sales and property chacteristics. Most agents offer free CMA'x - but in manjy cases you get what you pay for. You also can get a comparable sales report from companies that specialize in real estate data or find comparable sales information available on various real estate Internet sites.