color of someone's money, see the
Prove that you can pay, as in Before we talk any more about this car, let's see the color of your money. This term probably originated in gambling or betting. [Slang; early 1900s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.