in for a dime, in for a dollar

Etymology
Alteration of “in for a penny, in for a pound”, adapted to the denominations of the American currency (£ & d → $ & ¢). Nevertheless, “in for a penny, in for a pound” is used in the United States as well.

Proverb

 * 1)  Americanized form of in for a penny, in for a pound.