Price per 100 pieces?

Let us say one piece costs $10. So 10 pieces would cost $100. Say, if someone buys 100 or more pieces, you provide a 10% discount. In this case, 100 pieces would cost $900, 110 pieces would cost $990, and so the unit price would be $9.

Now, let's summarize the usage:

If you want to refer to the total cost for all 100 pieces sold as a single unit, use:

Price per 100 pieces

If you want to refer to the price of each piece, use:

Price per piece (or unit price)

If it is price of each piece when someone buys at least 100 pieces, use:

Unit price for a minimum purchase of 100 pieces

I think it is the last one you are looking for.

Hope this helps.

We call that "quantity pricing". So the price if you buy 100 is the Quantity 100 Price.

What do you think of this one?

It's quite short and clear, without having to use a word/phrase to explain it.

This website is using that pricing system, and I think it's understandable enough. (:

Maybe just to make it even clearer, change the title of the second column to "Price/Item" or "Price per Item".