The cheapest setup I have found:
Enclosure http://goo.gl/eiEW3 $269.99
Harddisks http://goo.gl/JZqtV $107.98 x 8
filesystem http://goo.gl/lnPoR $0
total $1133.83
offsite backup http://goo.gl/GMcih $3 / month
use raidz2 (or raidz) to protect against failing disks
use zfs snapshots to protect against accidental file deletion
use crash plan to protect against fire or theft.
Enclosure http://goo.gl/eiEW3 $269.99
Harddisks http://goo.gl/JZqtV $107.98 x 8
filesystem http://goo.gl/lnPoR $0
total $1133.83
offsite backup http://goo.gl/GMcih $3 / month
use raidz2 (or raidz) to protect against failing disks
use zfs snapshots to protect against accidental file deletion
use crash plan to protect against fire or theft.