does netsuite have a feature that calculates Purchase Order profitability?

do you mean sales order?

Following Nicolas, The Gross profit feature under Enable Features does this for Sales Orders

what about Purchase Orders? Something like (average cost - purchase price) would give me the estimated total profit per item ?

What you are referring to is not the profit per item but the purchase price variance from what I understand

Yeah maybe i did not explain that very well we need to have a field on a Purchase ORder, called estimated total profit, which consists of the sum of (sale price - purchased price) for every line item on a PO

ok - are you using the price list on the item record?