The first step in planning is to develop a unit standard cost for each element of variable cost, by product and package size. Examples of two different packages for one product are shown below. As already pointed out, the accountant can do this by using current prices and yields for material costs and current allowance rates for marketing costs. After the total unit variable cost has been developed, this amount is subtracted from the selling price to arrive at a standard marginal contribution per unit, by product and package type.