How can I display Product currant cost value on the Order Product form?

Hello,

I have a need to calculate an Order Product GP value, ie Total sell - Total Cost.  I can get the Total sell, based on the Quantity and Sell price because they are available on the Order Product Form.  But I am struggling to get the currant cost of the product from Existing Product record.  Any help?  We are using CRM 2016 online.

Please help.

Thanks

Lana