Green’s Dictionary of Slang

1. (US, also case note) $1.

1839		H Brandon ‘Dict. Flash or Cant Lang.’ in ‘Ducange Anglicus’ Vulgar Tongue (1857).
1859		Matsell Vocabulum.
1867		Nat. Police Gaz. (NY) 14 Sept. n.p.: The ‘beak’ [...] requested her to contribute fifteen ‘cases’ to the city.
1871		J.H. Banka State Prison Life 492: One dollar [...] One Case.
1888		Sun (NY) 13 May 14/6: Bones — cases; what was the boodle worth?
1896		F. Hutcheson Barkeep Stories 28: ‘Now dere ain’t hardly as much as ten cents in de gang, much less a ten case note’.
1897		E.W. Townsend Chimmie Fadden 23: Don’t you know what a plunk is? Why it’s a case, a dollar.
1904		Ade ‘The Fable of the One Who Got What Was Coming to Him’ in True Bills 72: Any time that he unwound the Shoe-String and disgorged a One-Case Note, he was expecting to get a Return of about $1.60.
1907		D. Runyon ‘The Defence of Strikerville’ in From First To Last (1954) 13: Two cases a shift for snoljering.
1910		Wash. Post 3 July 3/1: ‘What’s the matter, Hop, what’s gettin fierce?’ [...] ‘Why, the amount of hop you can get for a case note,’ answered Hoppy.
1916		J. Lait ‘Canada Kid’ in Beef, Iron and Wine (1917) 153: I goes home an’ I slips six o’ them ten-case notes to other lads.
1928		J. O’Connor Broadway Racketeers 250: Case Note — A dollar bill.
1931		M. Harris ‘Facing the Mob’ in Gangland Stories Feb. 🌐 I slips Jimmy the word and he comes back with a fifty-case note.
1949		Monteleone Criminal Sl. (rev. edn).
1962		Ragen & Finston World’s Toughest Prison 794: case note – A dollar bill.

2. a counterfeit crown (5s (25p)); thus half-a-case, a counterfeit half-crown (2s 6p (12½p)) [cite 1895, with no ref. to counterfeit, may be a mis-reading].

1839		H. Brandon Dict. of the Flash or Cant Lang. 162/1: Case – a bad crown piece. Half a case – bad half-crown.
1859		Hotten Dict. of Modern Sl. etc. 17: CASE, a bad crown piece. Half-a-case, a countefeit half crown.
1864, 1867, 1870		Hotten Sl. Dict. [as cit. 1859].
1909		J. Ware Passing Eng. of the Victorian Era 65/2: ‘Case’ is [...] thieves’ English for a counterfeit five-shilling piece.

3. (US Und.) one’s last dollar.

1931		‘Und. “Lingo” Brought Up-to-Date’ L.A. Times 8 Nov. K3: CASES: The last few dollars.
1935		A.J. Pollock Und. Speaks n.p.: Case, the last dollar.