I first saw one of these several years ago in a video but can't remember where. I decided to build a prototype out of as much as I had laying around the house. The fan costs me about $16 (including shipping) after applying the Amazon card I was given for Father's Day.
Definitely better than nothing but it does take more ice than I expected if you want something that cools long enough for an evening hog hunt.
A larger cooler and fan would no doubt produce a greater volume of cool air.
With this setup I figure I can leave the motor/top and a battery in the stand and just carry the ice chest and ice when I got to hunt. And of course the cooler will also keep beverages ready for consumption.
I seem to remember Academy selling these for several hundred bucks.12-volt fan on Amazon