I have seen some big cat santuaries put tigers and lions up for adoption at around that price (usually a tid-bit higher.) I would imagine the paper work it would take to be able to own one would be expensive and difficult to get, plus the expenses of caring for one, it would make sense if they weren't that much. Plus, its not like they are in big demand.
And need I remind yall http://ball-pythons.net/forums/showthread.php?t=85931