Our trucks are specced by bean counters who go home every night so consequently do not have fridges fitted. I use one of them 12/240v hobbies from Aldi, it isn’t a fridge per se but it a perfectly adequate cool-box. £40ish, worked well for the last three years.
If I need stuff a little colder my company have kindly issued me with a forty odd foot personal fridge that I pull around behind me all week.