Yes, compressor fridges are expensive, but if you add up the cost of ice, the extra gas to go buy it every few days, the wear and tear on your vehicle to get the ice, and most of all, the cost and hassle of all the water-soaked and ruined food, a compressor fridge is well worth it. We had a peltier excuse for a fridge out of ignorance, about 10 years ago. It ended up in the donate pile. Had a 12v/120v/lpg fridge and it was not much better.
You have to have enough battery power for the peltier or the compressor fridge or carry propane for the ammonia absorption fridge (and must stay fairly level). We ended up with a truckfridge/indel b/isotherm/vitrifrigo (same manufacturer, different quality /trim levels).
Ted