Green’s Dictionary of Slang

(orig. US) a great many, a good deal, a large amount; often of money.

1895		J. London ‘’Frisco Kid’s Story’ in High School Aegis X (15 Feb.) 2–3: Well, I guess I seed stacks like’m, but I never took pertic’lar notiss.
1896		‘Banjo’ Paterson ‘Hay and hell and Booligal’ (in Bulletin 25 Apr.) Of course, there’s heat -- no one denies -- / And sand and dust and stacks of flies, /And rabbits, too, at Booligal.
1902		Bulletin (Sydney) 15 Nov. 12/4: [L]ittle sister Dolly Castles warbled ‘Good-Bye’ with a fresh voice, stacks of confidence, and an artful touch of tenderness.
1903		A.H. Lewis Boss 59: They’ve put out stacks of money.
1906		N.Z. Truth 4 Aug. 4/5: [heading] But the Chief Justice Says He’s Got Stacks of Company.
1909		L.W. Payne Jr ‘Word-List From East Alabama’ in DN III:v 375: stacks, stack loads, n, Large quantities.
1919		J. Buchan Mr Standfast (1930) 692: Oh, yes, I know there’s stacks of good old Teutons come and squat in our little country and turn into fine Americans.
1953		W. Eyster Far from the Customary Skies 117: He has stacks and stacks.
1960		J.D. Macdonald Slam the Big Door (1961) 103: I got stacks of money, son.
1976		Cab Calloway Of Minnie the Moocher and Me 85: We were getting stacks of mail.
1994		F. Mac Anna Ship Inspector 158: Stacks of them. Absolute stacks.
2000		Ebonics Primer at www.dolemite.com 🌐 stacks Definition: large sums of money. Example: Damn nigga, you be makin stacks.
2001		N. Barlay Hooky Gear 156: Sensis cuzs gear which is mostly weights an weight trainin gear an stacks of mags.
2010		L. Redhead Thrill City [ebook] ‘How much ammo you got?’ ‘Stacks’.
2018-20		T. Thorne (ed.) ‘Drill Slang Glossary’ at Forensic Linguistic Databank 🌐 Stacks - large quantities of money.