I don't see a link to the home you're referencing, but it's common on Trulia foreclosure listings to show either the amount an owner is behind in payments or the first (or second) mortgage loan amount. They do not reflect other loans, tax liens, delinquent property taxes, or foreclosing lender fees that might also be attached to the property. In the vast majority of cases, the home could not be purchased at that price and in many cases the home isn't for sale at all. Usually the owner is either able to refinance, renegotiates their loan, or contacts a real estate broker at the request of the lender to list the property for sale. Most sell at or very close to market price.
Please let me know if I can be of further assistance.