Almost every business must invest in some major equipment, vehicles, machinery, computer or furniture in order to run. The IRS gives you a choice between two or more different techniques to choose from and they mandate a five year period. The best would be to place it as an expense. Any expense that is legitimately a part of an entity and doesn't fit somewhere else can go to miscellaneous expenses.
A depreciation scale is usually used for machinery and equipment that costs more. That way a little bit can be written off each year to counter the taxes that are paid. I would think that for only $400 you would write it off in just one year