This auction may be of use to people from the US :
http://cgi.ebay.com/Lot-of-250-Black-5-25-Floppy-Disks-New-Old-Stock-Disk_W0QQitemZ110025374045QQihZ001QQcategoryZ11164QQrdZ1QQcmdZViewItem
He's got a second lot listed as well - http://cgi.ebay.com/Lot-of-250-Red-5-25-Floppy-Disks-New-Old-Stock-Disk_W0QQitemZ110025396182QQihZ001QQcategoryZ11164QQrdZ1QQcmdZViewItem