ETA: Never mind about the closest second. But I still haven't beat that first Harry Potter. It's weird, too: virtually _all_ of the copies are .01 (unless they are fulfilled by Amazon and some of those are $3.89 which I didn't realize was possible, thus netting out less than the .01 when shipping is considered and assuming you have Prime), and certain stores (Yankee Clipper, Blue Cloud, etc.) show up with hundreds of entries on individual books.
The 2nd and 3rd Potter books also have lots of used .01 copies, however book 4 jumps up to over a quarter before shipping (and no < $4 fulfilled by, either) and the rest of the series climbs from there.