axle grease Australian slang for money, which greases the wheels of life, so to speak, helping things to run along more smoothly.
chicken feed Small change; a paltry or inconsequential amount of money. This American slang expression, which dates from 1836, is an allusion to the scraps and seeds fed to chickens.
fast buck Money acquired quickly and effortlessly, usually through illegal or unscrupulous methods. In this expression, buck carries the American slang meaning of dollar, making the origin of the term self-evident.
Trying to hustle me a fast buck. (A. Kober, New Yorker, January, 1949)
filthy lucre Money; money or other material goods acquired through unethical or dishonorable means, dirty money. This expression was first used in an epistle by St. Paul:
For there are many unruly and vain talkers and deceivers … who subvert whole houses, teaching things which they ought not, for filthy lucre’s sake. (Titus