by the gross

In large quantities. Although this definition is broad, a "gross," when used as a unit of measure, equals 12 dozen. We definitely have more paper towels somewhere in the house—my mom practically buys them by the gross. With five teenage sons, I feel like I buy food by the gross! We're cleaning out my grandmother's house, and she has bolts of fabric by the gross. Please tell me you know someone who sews.

by the gross

in large numbers or amounts.

A gross was formerly widely used as a unit of quantity equal to twelve dozen; the word comes from the French gross douzaine , which literally means ‘large dozen’.