Quantity Discounts

[innoplas]

I have created an order form we fill in while our customer is on the phone with us. We enter the Product ID and auto enter the description. We offer quantity discounts, for example; 1- 12, 13 - 24, 25 - 50, 51 - 100. How can I get the quantity discount price to be automatically entered based on the quantity we enter in the quantity field?

Thank you in advance for your help.

Gary