Green’s Dictionary of Slang

(US black) money.

1984		Toop Rap Attack 158: Gusto: money, cold cash, dinero....‘Hey man, it’s Monday. Where’s my gusto?’ [HDAS].
1989		Public Enemy ‘Black Steel in the House of Chaos’ 🎵 I got gusto, but only some I can trust, yo.
1995		L. Stavsky et al. A2Z.