There are several free backup services and most of them come with storage constraint of a few GBs one can store.
How about using your friend’s PC for storing your data?
BuddyBackup, as the name suggests backs up your files over the internet onto your buddies’ computers.
Once you’ve installed the software, you choose which files you want to backup, add your buddies (just like you would in an Instant Messaging program), and that’s it. BuddyBackup uses the AES encryption system (a standard recommended by the US Government) for data encryption and can even backup to a removable drive/stick using USB or FireWire (IEE 1394).
BuddyBackup sends the updated files to your buddies (see 5) over the internet. Remember that only changes within your files are sent . BuddyBackup uses advanced Peer-to-Peer technology to ensure you can connect even if your buddies are behind a firewall or router.
If no buddy is currently online, BuddyBackup will keep track of the changes and back them up later.
BuddyBackup uses your internet connection smartly by only using a trickle of your bandwidth when you’re using your computer. This means you can continue to work while BuddyBackup is backing up your files.
After the initial backup, you’ll find things even quicker. BuddyBackup only sends changes within files over the internet. So, for example, if you add a few paragraphs to a big Word document, only those changes are sent, instead of sending the whole file again.
Finally, if you’re geographically close to your buddies, and can get a USB drive or DVD to them, you can speed up the backups (and restore) using the Import/Export feature. This allows you to export your backups temporarily onto a USB drive (or other location). You then pass this to your buddy who imports them onto his PC (when you get the USB drive back, you can safely remove the files). Note that the files are encrypted before they leave your PC, so this process is just as safe as backing up over the internet. This means you can speed up backups greatly, but still have the benefits of a online and off-site backup.