I picked up a few old Billboard magazines today, in a garage sale, from the late 1920s and early 1930s . I thought some of the old slot/vending machine ads were interesting. The only name I had heard of was the H.C. Evans Co. I was really hoping to find some magazines from the 1940s or 50s but, no dice there. I bet there were some Las Vegas ads in the newer issues. I would imagine these machines all predate the illegal club/Vegas stuff we are all familiar with.