Many companies offer unlimited cloud storage:

Amazon: $60/year

https://www.amazon.com/clouddrive/unlimited

Crashplan: $60/year

https://www.code42.com/store/

BackupLizard: $36/year

http://www.backuplizard.com/

Backblaze: $50/year

https://www.backblaze.com/best-online-backup-service.html

Carbonine: $60/year

http://www.carbonite.com/en/cloud-backup/personal-solutions/...

AltDrive: $44.50/year

http://altdrive.com/pricing.html

NitroBackup: $39.95/year

http://www.nitrobackup.com/plans-and-pricing/