Around the turn of the last century, 1900, a lot of inexpensive Euorpean pistols were around. They were marketed for many different reasons--cycling, "women's guns", kit guns, etc.
They received the moniker "Suicide Specials" as they were allegedly used for suicide as they were very inexpensive and not made for durability. At the same time there was a Southern expression [I use this word for historical purposes not as an insult] "Niggertown Saturday Night" that was used to describe gambling, drinking, disorderly conduct, etc.
The two terms combined to define a inexpensive pistol lacking in "quality", "Saturday Night Special". Dodd and Kennedy railed against these weapons (this term) in the '60s, as they were the "weapon of choice" (sound familiar?) of juveniles (who were blamed for crime) and urban blacks during riots in the '60s.
Prohibiting cheap weapons is not a new idea. Many Southern states did exactly this after the Civil War ended slavery, e.g. people could only carry "Army" pistols which were more expensive than cheap copies. Of course, King Hank II in the 12th century England did this to prevent Jews from bearing arms.