In the same vein as the other two threads, which seem to be pretty popular, I'll start with... a fully transferable Thompson M1A1. That would have been a pretty good investment in 1969 (I was 21) and a lot of fun to shoot.
Back in 1960, as a ten year old, looking in the back pages of my Outdoor Life magazine…type 38 Arisaka carbine 29.95, SMLE 39.95, K98 49.95, 1903-A3 and P-17 59.95. I believe you could also buy a complete, running WWII Jeep for less than 150.00…ahhh the good old days.