The protecting powers insisted on a per capita minimum of some things and parcels of surplus value were delivered regularly. It altered the economics. Accumulated surplus could be seized, by camp authorities or for redistribution by the prisoners self appointed authority or for "X" (escape and subversion)
Russian POWs had a different economy: they had no protecting powers having not signed the geneva conventions. As did concentration camp victims. Primo Levi wrote in "the periodic table" about stealing welding ignition bars to scrape down to size and resell as lighter flints, to survive.
Prisoners sold art and crafts. Prisoners bartered goods from the red Cross parcels for favours. There was probably a complex exchange of goods for favours, for sex, and sex for goods. Within the prisoners and with guards and wider society.
Scarcity value and exchange value and inflation were probably as distorted as in eve online.
Kurt Vonnegut wrote about labouring in a maltose syrup factory, and working to clear bodies in Dresden. Non commissioned and other ranks POW worked for cents per day, mandatory sometimes. Officers did not have to work.
Solzhenitsyn writes in "Ivan Denisovich" of the economy of the gulag. Not a POW camp but perhaps not dissimilar?
The economics of survival are complicated. Primo Levi carried lifelong burdens as a camp survivor. He's on record in "the drowned and the saved" and "is this a man" as saying to survive demanded compromises to avoid being what he calls a "musselman" fated to die sooner or later.
Interesting read. My grandfather was the "cigarette officer" in Stalag Luft III (the Great Escape PoW camp). His duty was the distribution of the incoming Red Cross cigarettes. The job was his due to the fact that he didn't smoke (at least that's what I was told).
He was also on the list to get out in the Great Escape - but was far enough down the list to never make it out of the tunnel. His job during tunnel construction was sand dispersal - socks down trousers that were released in the middle of a game of football.
A fascinating read, and it touches on many, many aspects of WWII PoW camp life as described by Eric Williams  in The Tunnel, which is contemplative and introspective, in contrast to the heroic and dramatic tone of The Wooden Horse, to which it is the prequel. (A film  of The Wooden Horse was made in the 1950s.)
I first read The Tunnel at age 11, and have read it at least once a year since. I've gone through so many copies; they just fell apart because of the heavy use. I have no idea why I find the book so compelling; perhaps just the wonderfully observed details of everyday life in captivity, and the skill of the author in portraying the characters with real depth and humanity.
A brief check online suggests that The Tunnel is still available in print, but it's also available online .
I find it remarkable how this paper is often cited in orthodox economics for an example or proof of Mengerian’s theory that money emerges from a proto barter-economy with the currency, the medium of exchange, being a good with intrinsic non-repudiable utility with rejection of need for base cooperation.
Meanwhile, if you read the paper, the author makes quite the opposite statement, that money and medium of exchange emerge as credit in cooperative societies and they rather focus on solving the problem of finding a unit of account on some commonly used good - which resembles a more Chartalist account of the emergence of money in societies.
Hence, this paper is actually a counter argument to monetarist ideas, and gives more credence to the Keynesian assumption that debt/credit relations between economic actors play a non-neglectable role in the behavior of agents.