Particle used for traditional numerals?

What is the particle used for traditional numerals (mittsu, itsutsu, kokonotsu,etc)?

The question went something like:

mittsu ___ hyakunen desu.

The translation was 3 pieces cost 100 yen. What particle should be used here?

Mittsu de hyakuen

(not "hyakunen").

The choice of particle has nothing to do with the use of traditional numbers, by the way. It would be the same no matter how you count.

Sanbon (3本) de hyakuen

Gomai (5枚) de hyakuen

Zenbu (全部) de hyakuen.

The important point is the function of "de" in this usage. It indicates that the number of things before is treated as a single unit.