Realty Trac dollar figures have no relationship whatsoever to house prices. The reason Realty Trac puts these dollar amounts into Trulia is to entice consumers into subscribing to their service in the hopes of getting the "scoop" on houses that are about to be foreclosed, or may be foreclosed upon (or not) at some future time.
Many houses that Realty Trac "tracks" will never be foreclosed upon, and almost none will be offered for prices significantly below current value minus the costs of repairs.
As a professional who buys foreclosed properties, I can assure you that foreclosures almost never sell for pennies on the dollar. Unless you are measuring the value at the bubble peak from 2005 If you do that, then almost every house in California is worth a fraction of its peak value, ...not just foreclosures.