What kind of costs are assigned to a specific item.

Hi, What kind of costs are assigned to a specific item. I mean to say,where do you say for a specific item only Material cost and material overhead cost should be calculated and not other types of costs like resource cost etc.  

Second, say if you ship confirm an order consisting of an item, and if the item price is say 150$, then is the cost of the item in the material transaction same as $150, so is the revenue amount same as the cost item ?

Can you please share your thoughts.

Thanks,Lakshmi N Jagarlapudi.