I've got several cloud, accounts including Dropbox, Box, Google Drive & Skydrive. All these are free, I think Dropbox started with 2 or 3GB and could be increased with things like liking on Facebook, following on Twitter etc. Google Drive starts with 5GB, it's the cheapest of the cloud accounts I have to upgrade but has the least functionality especially compared to Dropbox.
Box has limited upload file size when using the application and then there's Skydrive which anybody with a Hotmail account has but does not have an inhouse application.
On a side note, anybody that uses these should try Solid Explorer. You can set up cloud connections and functionality here beats the applications including Dropbox's which is by far the best of the four.