In the current climate I`d say the apt was either a fake or not as attractive as you would want.
There is a lot of property for rental and prices have reduced, but too 400.00 euros and it wasn`t snapped up in a few days i`d bet money there is an issue with it.
Site`s make money from visitor numbers, the more attractive the site, the more visits = more cash for the owners.
Facts on the net are rare.
I would make a trip to Spain and view properties first hand, if you are coming with no means to return home on the hope you can get a cheap flat in a reasonable ares, i`d advise you think hard about it first.
Although a landlord would wish to rent, they rarely rent at a loss, most prefer to leave empty than only just cover the mortgage, especially when there is risk of damage etc from bad tenants, low rentals are usually ignored.