I run an online company selling antique collectibles.  I do not use the inventory module because all the items I sell are one-offs, so i just record the sales via a general journal entry.  One of my biggest expenses is shipping supplies, like boxes, packing tape, etc.  I have found a new, less costly vendor for these items but they take orders by fax on a PO.  I have setup "service" items for the things I order from them, set the retail to a penny (since I will never be selling these goods), and setting the expense account to my "5635 Shipping Supplies" GL acct.

So now, what I'm hoping will happen is this: I create Purchase Order by selecting the service items I've created; once the order is received, I convert it to a Purchase Invoice, which then immediately expenses the cost to "5635 Shipping Supplies", allocates the amount due to "Accounts Payable", and that's it. 

Will I achieve this with the way I've set things up?  Is this the most efficient way of doing this, or is there a better way?

Thanks!

--Andrew