A sporting goods manufacturer budgets production of $45,000$ pairs of ski boots in the first quarter and $30,000$ pairs in the second quarter of the upcoming year. Each pair of boots requires $2$ kilograms $)$ of a key raw material. The company aims to end each quarter with ending raw materials inventory equal to $20\%$ of the following quarter's material needs. Beginning inventory for this material is $18,000kg$ and the cost per $kg$ is $$8.$ What is the budgeted materials purchases cost for the first quarter?

$$720,000.$

$$672,000.$

$$576,000.$

$$729,600.$

$$864,000.$