The Forgetful Builder

You've just purchased your first new home. When you arrive to beginning moving in, you discover that the builder forgot something. Being a self-reliant sort of person, you decide to finish the job yourself. You stroll down to the local hardware store and find exactly what you need at a price you can afford. The hardware store charges perfectly reasonable prices for the items; 7 will cost $1.00, 10 will cost $2.00, and 100 will cost $3.00. As it happens, you need 880, which also costs $3.00.

These items could likely be found at any hardware store, and at your average home.

What did the builder forget?