On my 5th or 6th re-read of the series recently, I was struck by the basic incoherence of the principles which underpin the wizarding economy. Essentially, there is no scarcity. You need food? Gamp's law of transfiguration says that as long as you have some, you can increase its quantity as much as you want. Limited space an issue? Just build a room of requirement which can expand or contract with the wishes of the user. Issues like these bug me, somewhat destroying the realism of the novels.
But more relevant to budgetary concerns is this puzzling fact. Once students graduate Hogwarts (or Beauxbatons or even (heaven forbid) Durmstrang) there seems to be very few employment oppurtunities available. Either you join the Ministry of Magic, whose entire purpose is to keep the muggles oblivious. Or you become a teacher. Or you work on Diagon Alley in a retail store. There seems to be very little primary commerce going down in the wizarding economy.
Of course for wizards, this is not an issue, because they can just substitute magic for industry and everthing is sweet. But supporters of big government spending who believe that this can pump money into an economy and stimulate employment should learn from this. Maybe it would work if Dumbledore was the Minister of Finance. But for those of us tethered to the muggle realm, conjuring economic productivity is not so simple.
Thus ends my frivolous take on macroeconomics.