Sync lets you sync files securely and more privately than most other services. And their client still supports XP. You get 5GB free storage for signing up. If you do some instructions they tell you they give you 1GB more and if you do the Konami code while logged in you get an additional 1GB. That's a total of 7Gb free.
You can install in I think it was 3 or 5 devices. That includes your computer or phone. Or you can manage everything on the web. That doesn't count as a device.