Create Purchase Order for items for office use, i.e. Office Supplies

What is the best way to set-up and create purchase orders for non-inventory items like office supplies? 

We are a manufacturer, but these items are not stock items, nor are they raw materials.

Our process is to create a purchase order for any purchases over $500.  The PO needs to list a description of the item, price, quantity and extended price on the invoice.  A receipt is required for all items on the purchase order.

Obviously, we don’t want to set-up item IDs for all these miscellaneous and one-off purchases.

Thanks for the help.