I'm as cheap as the day is long, and I have come up with limited ways to mitigate the expense of going to Alaska.
Particularly, get a TOursaver book at
www.toursaver.com.
But (1) food and lodging are fundamentally expensive during the "tourist" season, and (2) activities are more.
I have concluded that one is best off saving one's pennies until they can do Alaska "right", which involves some outlays.