Filesharing service Box is offering up 25 GB of free cloud storage in a new promotion (supposedly for "Gameday," but it seems to still be in effect anyway). To qualify, you must be a new customer on a free plan, or just sign up for a new account with a new email address. The deal is also for non-commercial use only, and because it's free, there's a file-size cap of 250 MB that you'll have to duck in under.
But even with those catches, who couldn't use some extra storage, right? Box's deal is as up for as long as they leave it up, so definitely jump on it soon if you're interested.