Here is the story I have bunch of products that they can be added to "Add Quote Item" I want to be able to get all the products that are taxable first (Use a boolean and then the agent will check mark each products and saves it.) then be able to say if there is a check mark on the product add them all up and then multiply it with taxes ... I may not have much of idea Can we have this formula field IF(CONTAINS(Tax__C = True) Then (UnitPrice * Quantity ) * Tax)
Posting comments as answer per request.
I am assuming you want this field to be on the opportunity? If so, have you tried to create a roll-up summary field then use that field in the calculated formula field?
You can use a workflow rule to set the value of a text field on the OpportunityProduct to the value of the desired product2 field. Then use that in the roll up summary