If you're using a floppy at the moment it would appear that you don't have much to backup.
The cheapest option is a USB memory key (pen). You can get 128Mb for about £30 on Ebay. A new HDD or CDRW drive will be about double that.
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Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.