Green’s Dictionary of Slang

1. (orig. UK Und.) a shilling (5p).

a.1790		H.T. Potter New Dict. Cant (1795).
1809		G. Andrewes Dict. Sl. and Cant.
1829		Reading Mercury 6 Apr. 4/5: A pair of tough cotton cord Kicksies, built quiet or fierce: Eight-and-twenty peg.
1830		Birmingham Jrnl 10 July 3/4: [W]itness asked Smith the price of various counterfeit coins, when she said cooters (sovereigns) were 4s. 6d. each; tusheroons (half-crowns) 5s. a dozen; pegs (shillings) seven score for 20s.
1840		Flash Mirror 21: It is all a bleeder, and [he] offers a reward of ten peg to any kid who will blow the cove that said it.
1840		Courier (Hobart, Tas.) 27 Oct. 3/1: [advert, from UK source] [S]lap-up full dress Togs. 2 couters, 3 quarters and a peg.
1848		Flash Dict. in Sinks of London Laid Open 118: Peg, or peg stick, a shilling.
1857		advert in ‘Ducange Anglicus’ Vulgar Tongue (1857) 45: Slap up Velveteen Togs, lined with the same, 1 pound, 1 quarter and a peg.
1860		Hotten Dict. of Modern Sl. etc. (2nd edn).
1870		Hotten Sl. Dict.
1882		Sydney Sl. Dict. 9/1: The Schoolmaster draws fakements up; he’s tipped a peg a-piece. The Schoolmaster draws up begging-letters and placards; he is paid a shilling a-piece for them.
1887		Daily Trib. (Bismarck, ND) 23 Oct. 4/1: Small silver coins are ‘pegs.’.
1894		Truth (Sydney) 14 Jan. 6/7: When the chump puts out his mauler I gives him nine peg (i.e. shillings).
1905		Exeter & Plymouth Gaz. 4 Feb. 5/6: The names for a shilling include [...] a ‘peg’’.
1910		Truth (Perth) 5 Mar. 9/8: She tips me / Five peg over of me fare.
1919		Smith’s Wkly (Sydney) 7 June 9/6: Slang of Money [...] A shilling is a ‘bob,’ ‘blow,’ ‘peg,’ ‘dener,’ ‘north-easter’.
1946		Sun (Sydney) 29 Sept. 15/1: When King became Gov. in 1800 he discovers that these smart alecks were bringing the stuff into the smoke for eight peg a gallon and the public were buying it for two smackers.

2. (US) a small sum of money.

1890

Nat. Police Gaz. (NY) 31 May 2/3: I was on my uppers, and I couldn’t produce a peg to get a drop of bug juice or a smell of fizz.

3. (Aus. Und.) two shillings.

1950

S.J. Baker in Sun. Herald (Sydney) 8 June 9/3: The underworld has an extensive vocabulary of financial terms. Among those recorded by Detective Doyle are: ‘Deuce,’ ‘swy,’ and ‘peg,’ two shillings.