Try checking out your local pawnshops for generators and ac units. I work at one in Lake Charles, and we get practically brand new ones in after every hurricane season which we sale for less than you can buy them new.

Also, I freeze one gallon jugs of water (usually 4) then just rotate them to the lower part of the fridge and refill those from other jugs until the ice fully melts. not only do you you have large quantities of ice on hand, but also wonderfully cold water to drink at all times. It also cuts down on the amount of electricity required to keep your fridge cold.

Truckergut