Restored in working condition maybe $2000 in non-working condition your lookin' at about $200 to $350.
It will set you back around 125.00, but if shop around you could probably find it under a hundred. The Broan 35316 Gable Mounted Powered Attic Ventilator fan costs about the same as, and on some sites, you can find it for less than, the cost of your everyday ceiling fan. Costly also being a relative term, the fan goes for about $110.