http://www.ebay.com/itm/USB-Floppy-Drive-Transfer-Between-Latest-Mac-and-Vintage-Mac-/171745827898?pt=LH_DefaultDomain_0&hash=item27fcd95c3a
May not be the cheapest on eBay but I can vouch for the seller and the drive. It may say Toshiba but it's a high quality TEAC drive, and it works just fine with iMacs and OS 9. It won't write an 800k Mac floppy though, as has been said, so you'll need to take things to the PowerBook, then use the PB to make 800k diskettes. Also, you really can't format a 1.44MB diskette as an 800k unit, you'd need real 800k diskettes.
May not be the cheapest on eBay but I can vouch for the seller and the drive. It may say Toshiba but it's a high quality TEAC drive, and it works just fine with iMacs and OS 9. It won't write an 800k Mac floppy though, as has been said, so you'll need to take things to the PowerBook, then use the PB to make 800k diskettes. Also, you really can't format a 1.44MB diskette as an 800k unit, you'd need real 800k diskettes.