The deal is that for a $5.00 donation to the Greater Chicago Food Depository you get a shopping bag and can fill that bag with as many books as you care to from the boxes arrayed outside the store (a couple of dozen good sized boxes). I ended up leaving with 20 titles, with the "prize" being Abrams' 1981 behemoth "Treasures of the Library of Congress" in great condition (originally published at $75)!
My back would have been much happier if the book boxes had been up on tables (they were arrayed all over the sidewalk), but I guess "beggars can't be choosers", and for an average cost of 25¢ a book, I was pretty much in the beggar category. I also had occasion to question my near-avaricious acquisitiveness, as, with the construction re-routes caused by the El revamp at State & Grand, I had to walk my literary loot three blocks to catch a bus. I had, however, been hoping for a new influx of books (that I didn't have to pay retail for), so this was quite a treat.
For those Chicagoans reading this ... I'm pretty sure they're running the sale (and I suspect they're not done bringing out caseloads of books) through 7pm this evening!