chicken scratch, n.² — Green’s Dictionary of Slang

chicken scratch n.²

[? the small impression it makes on one’s expenses; or chicken adj. (1) + scratch n.³ (5)]

(US black) a very small amount of money.

1994		C. Major Juba to Jive 91: Chicken scratch n. (1940s–1950s) a small amount of money.
2002		D.H. Sterry Chicken (2003) 25: I made seventy-eight dollars after taxes. That’s chicken scratch.