My former Burro
had a little electric fridge like that. Wouldn't keep food cold for more than 4 hours, which didn't fit my traveling style. I use it to store bread and chips, and bought a big $50 or $60 cooler. The cooler could keep ice for 2-4 days.
Burr, if you need to economize, you might look for used ones. There's a huge RV boneyard in Missouri along I-44; places like that might have the right size. Other than that, a new Dometic or Norcold are an arm and a leg, and I've never seen them discounted much anywhere. I was looking, too.