I disagree. Cosmic Charlie. In many instances it has nothing at all to do with saving money. There is the matter of CONVENIENCE!! We will be bringing or purchasing a cooler as well. I have a baby who is still drinking from a bottle, and a toddler who prefers peanutbutter and jelly over anything else. The rented fridge is not very large and a cooler suits us better. Having a gallon of milk on hand at 1 a.m. to make a quick bottle sure is terrific. And certainly whipping up a peanutbutter and jelly sandwich whenever my 4-year old craves a snack, or giving him a cup of juice when he wants one, is a lot easier to do when these items are in your room -- in a cooler -- and not a building or two away at a food court or snack stand.
I think everyone has had good suggestions. Since we don't already own a hard-sided cooler, and I'm not sure we'll be able to find the packable one, we will probably pick up the styrofoam-style at the grocery store when we arrive.
(Edited for spelling.)