How about selling DVDs burned with collections of PD books, reading apps for all the major platforms, and Calibre? The cheaper DVDs featuring single genres and the top of the line bearing a whole Gutenberg or Black Mask library. Plus whatever else the likes of us can point you to. The sheer numbers should draw attention. It'll promote reading. And ebooks, too.
A lot of people don't know the stuff exists and other than the blank DVDs and Labels the costs are nil. (Might as well put your Mobileread expertise to use.
)
A raffle for a few eink readers and a tablet. (DITTO.)
Otherwise, I suppose you could sell Kindle- and Kobo-shaped cookies.