If you are just wanting a place to backup, you can get a Copy.com account and then use fiverr.com to have someone get you an additional 500GB of storage through referrals. I'm honestly not sure how they do it, but I paid $10, and had a full TB of additional storage added to my copy.com account in under 24 hours.
And since it is through referrals, it should stay a full TB forever without monthly or yearly fees.