twenty, n. — Green’s Dictionary of Slang

twenty n.

also twennie

(US drugs) $20 worth of a narcotic drug.

1989		(con. 1982–6) T. Williams Cocaine Kids (1990) 43: I don’t put but a few twennies [$20 packets] in foil anyway ’cause if you sweat too much it cakes up.
1992		T. Williams Crackhouse 69: He threw a package of twennies – about four of them – at me [...] A ‘twennie’ is an aluminium-foil packet of cocaine, worth twenty dollars, prepared for quick sales.
2001		ONDCP Street Terms 22: Twenty — $20 rock of crack.
c.2003		D. Vrij ‘Tying Off’ on Inter-zone.org 🌐 By day, and into the evening, heroin and powder cocaine were cheap and abundant, the $15 smack quarters, were fatter than the downtown 20s, all night long the flailers, could pick up on whacks of speed.
2008		R. Price Lush Life 342: An ounce [...] could be bagged up into twenties or forties, or straight hundred-dollar grams .
2021		T. Swerdlow Straight Dope [ebook] She spits a small green balloon out of her mouth that looks a dime but might be a twenty.

twenty and forty (n.)

(US black) $20 worth of marijuana and a 40oz. bottle of malt liquor.

2002

Cypress Hill Sl. Gloss. 🌐 twenty and forty: hip-hop term for a $20 bag of reefer and a 40-ounce bottle of malt liquor.

twenty in the pounder (n.) [i.e. twenty shillings to a (pre-decimal) pound]

one who pays their debts in full rather than opting to pay in instalments.

1909