One can insert, in context, a cost at one point.  For instance, "The 'one-time-buy' of M16A1 rifles by the US Army was for a unit cost of $100." Even then, contracts are not exact either.  A contract can have penalties, incentives, delivery costs, support costs, development costs, and an absurd array of factors which make any one number meaningless.  Take the B-2 (if you're fond of aircraft. Prices for individual planes hovered between $277m and $1.1b depending on who you asked.  Prices, when they included the cost of development and support infrastructure have topped $3 billion.  That's a lie, of course.  If you were to have added one bomber to the end of the production run, it would have cost around $350m extra.  Is that the actual cost of the bomber then?