mammy, n.² — Green’s Dictionary of Slang

mammy n.²

[the image of maternal, i.e. mammy’s abundance, of love, food etc.]

(US Und.) an abundance, a lot, esp. in phr. money’s mammy, a great deal of money.

1942		Amer. Mercury LV 92: What I want to steal her old pocketbook with all the money I got? [...] I got money’s mammy and Grandma change [DARE].
1971		H.E. Roberts Third Ear n.p.: mammy n. the ultimate; the most; e.g. A wealthy person is said to have money’s mammy. There is confusion’s mammy in that room.
1992		Bentley & Corbett Prison Sl. 15: Mammy An abundance. A person with four cartons of cigarettes has cigarettes mammy.