There is a nice history of the Exhibit Supply Company here:
https://www.madeinchicagomuseum.com/...bit-supply-co/
As noted in that article, Exhibit Supply Company started actively marketing the machines to drug stores starting in the 1920s. That was about the same time that their first baseball set came out (1921).
Back then, drug stores were a center of retail activity where you bought candy, cigarettes, newspapers, etc. They also had soda counters and people hung out. I got all my first sports cards as a kid in the 1970s at several drug stores in my hometown.
Hence, distribution would have been pretty mainstream in the USA.
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