How the $8,000 Tax Credit Cost Home Buyers $15,000

``The median home value fell to about $170,000 in March from $185,000 a year earlier, according to Zillow.com. That means a buyer who closed on a house just before the tax-credit program expired in April 2010 collected $8,000 but has since lost $15,000 in value. Those who bought earlier in the program have done worse; the median price is down $20,000 from March 2009.''