You can even go on Zillow.com and look up any address to see what houses are selling for and what houses in an area recently sold for and the month they sold along with exterior and interior pictures of the homes.
Housing sell prices are public knowledge. What is NOT is what negotiations went into the price. You can buy a home for $500k and have the seller pay $10k in closing costs and you put down $50k. You now owe $440k on that home but the sell price is still listed at $500k.