I have been sous vide-ing in a semi decent Coleman Cooler (celotex base & lid) temp drop restricted to around 5 C per day when not in use.
Emptied it out (secondary use) & screwed lid back on so daughter could take it camping for a food poisoning free experience

I'd cooked them off a loin of pork to cut chunks off & pan finish in butter, (60c for 3hrs) otherwise it was burgers & hotdogs.
My concern as ever is the hot/ cold leakage from what are meant to be respected manufacturers..
When empty & in proper cold block use, the lid gap is semi open (loads of leakage potential) you can slide sheets of paper through the gap.
Even more so when semi filled with water (distortion of plastic & foam shell)
Made me wonder, in this age of modernity, if the degree of heat / cold leakage was the reason these things don't come with a basic clip in thermal sensor + outside display pocket, ..so that's what I'm going to do. (Curiosity, & checking for even temp back to front when heating water)
Anyhow, the place in the link above is cheap of late if anyone is after some *basic* digital thermometers & more, the eBay price over the past 12 months has been crazily high) ..nb, batteries not included.
I've bought a few for water distillation, home brew, fish tank etc, in case anyone is after this sort of non critical kit (awaiting delivery)