Office paper / copy paper / printer paper, by the ream or by the case.
Some of the brands are common across stores, so that opens the possibility of pricematch combination deals. I don't have a good sense of this stuff yet but I have a feeling there's a killer deal out there waiting for someone to find it.
$30/case seems to be the going rate after normal discounts. Can we do better?
(Note that *most* cases are 10 reams / 5000 sheets, but some sneaky folks make 8-ream cases...)