Interesting list - it’s amazing to me how relatively inexpensive most of the guns were with a few exceptions like the Thompson Submachine gun. It cost $209.00 in 1939 (3500 in 2015 money) . Also the Browning Automatic rifle was 319 in 1945 which was not cheap in those days and is $ 4207 in today’s money.
I notice the older designs like the Thompson and B.A.R. guns tended to be more expensive. My guess would be that later designs were optimized for newer mass production technology. During WW2 the demand for more guns was absolutely bottomless and machine tool capacity maxed out. A strong emphasis was placed on economy both of production and tooling required. Particularly, the M3 “Greasegun” and the Sten were expressly designed to be constructed as much as possible from stamped steel, rather than milled parts. They looked like pieces of tin but they got the job done.
As a footnote, the ultimate cheap gun was planned to be the FP-45 “Liberator”, a better-than-nothing gun that was planned to be produced in the millions and dropped over occupied territories to flood the countryside with illicit guns for use by resistance fighters. It’s been described as “a good gun to get another gun with”.
$83 1942 dollars is now $1223.18. Suddenly $730 for a Service grade Garand or $1030 for a Special grade doesn’t sounds so bad. On the other hand, M1 Carbines were only slightly more expensive that you could get them for now (when the CMP had them a little while back).
On the other hand, that $3500 (or Wolfram says $3617.10) fully automatic Thompson has appreciated in value considerably (I don’t know if this one was typical). I realize that this is production cost vs. purchase price now, and greatly inflated due to extremely limited supply and Class III stamp +$200 and a bunch of hoops to jump through.
This is lacking Soviet guns (or Japanese) so I’d really be curious about those. Mosin Nagants doubled in price the last 2 or so years but still cheap.