I'd love to have an Engle, or similar, but as with many, there always seems to be something else that needs money spent on it, For now I use a Coleman Extreme ice chest. When my son and I left for RTR last month it was of course below freezing in Colorado, but thankfully warmed up nicely by the time we reached RTR. Our ice chest is 70 quarts size, and I put 4 large juice bottles with water frozen in the ice chest. I also put all the meat we took into the ice chest frozen. But things like milk, eggs, vegetables, etc... were of course just cold and not frozen. After 6 days there was still a little tiny bit of ice in the bottles, and what was left of the food, and more importantly the beer, was still cold. On the 7th day I bought a block of ice and that was all the ice I bought for the entire 15 days I was on the road. I tried not to ever leave the ice chest lid open while I was cooking, but I did get into it several times each day.
Hopefully that gives you a good comparison for what a good ice chest vs a cheap one is capable of. And if you do ever get the funds for a fridge the ice chest still makes a great back up, or just dry food storage. As others have noted, I wouldn't waste my money on one of the thermal electric coolers. And as much as I think they're cool, I also wouldn't go for the really high end ice chests like Yeti's. A good Coleman or other brand that is listed as a "5 day" cooler will serve you well for your needs.