Green’s Dictionary of Slang

pertaining to cheap goods, in poor taste.

1872		Arizona Citizen (Tuscan, AZ) 22 June 1/5: The swarm of flunkies, Cheap John clothiers, etc., shut the shop door.
1880		Nat. Police Gaz. (NY) 10 Jan. 15/1: Flash pictures, gaudy decorations and Cheap John furniture abound .
1882		Dundee Courier 5 June 3/6: William Taylor [...] doing a very extensive trade in a tent [...] on the ‘cheap jack’ system, was summoned for keeping [...] a lottery.
1905		J.W. Carr ‘Words from Northwest Arkansas’ in DN III:i 74: cheap John, adj. In poor taste, low-bred, vulgar. ‘We don’t want any cheap John shows in this lecture course.’.
1912		S.F. Call 16 June 3/4: The Stanford period was the golden age for cheapjohn newspaper men.
c.1930		(ref. to 1868) N. Kimball Amer. Madam (1981) 49: The raw clods and the cheap-john coffin.
1933		(ref. to 1970s–80s) H. Asbury Barbary Coast (2002) 102: Cheap John clothing stores, which catered principally to sailors and fleeced them unmercifully.
1951		(con. 1880s) S. Longstreet Pedlocks (1971) 77: I’m an old man now [...] pottering around with rancid children in some river-front slum, running a Cheap John clinic.