Sales Order (fields locked)

I need to create a sales order (from scratch) and have the ability to change the price.

Actually none of our products have a price so I always need to add a price.

We are using CRM 2015 Online.

When I create a sales order and add a product, select Override Price, the Price Per Unit, Volume Discount, Amount and Extended amount fields are all disabled.

I actually cannot even click on the Write In radial box.

How do I change this behavior.

Thanks in advance