It's my guess, that this has to be part of her plan, to reestablish her broken record as well as gain Beltway experience. Because of her relentless campaign for McNuts in 2010, Palin has gained popularity in Arizona and could probably win.
Palin will need the same RINO millionaires as McCain(like Jim Click) to pull it off, but I fear you are correct. It cost McCain 21 million to beat Hayworth(1.6 million)