Grass Eaters, a manufacturer of lawn mowers, predicts that it will purchase $264,000$ spark plugs next year. Grass Eaters estimates that $22,000$ spark plugs will be required each month. A supplier quotes a price of $$7\mathrm{.}00$ per spark plug. The supplier also offers a special discount option: if all $264,000$ spark plugs are purchased at the start of the year, a discount of $4\%$ off the $$7\mathrm{.}00$ price will be given. Grass Eaters can invest its cash at $10\%$ each per year. It costs Grass Eaters $$250$ to place each purchase order. $$