OneDrive has been quietly expanding its functionality over the last while, increasingly echoing the UI of Office365 (with the numerous apps shown as tiles on the upper left of 
the screen).
As well as offering a tier of free storage (recently upped to 15Gb), it’s possible to buy additional space for your stuff – from a modest $2/month for an additional 100Gb, to a frankly bonkers offer if you sign up for Office365 Home at $10/month, with copies of Office for up to 5 users, 60 minutes of Skype calls per user, 1Tb of storage each and a bunch more. See here for info.
In the meantime, however, OneDrive has also been falling over itself to give users additional storage in exchange for doing something. (Check out your own storage quota and options here). You could refer your friends (get up to 5Gb free), if you set up your phone to back up photos, you’ll get another 15Gb for nada– plenty of storage for all those photographs you like to take on your handset.
Bing Rewards members can get a whopping 100Gb (cor!) just for signing up. Hint: if you are in a country that gets an error saying “This feature isn't available yet in your country or region” when you try to sign up, you might want to try clicking on the settings cog 
in the top right of that very page. If you happened to temporarily set your Worldwide region to be US – English, then you may have better luck. Just an idea.
Drop the box
If you happen to use DropBox (Win8 app here, WinPhone app here), or more correctly if you happen to have a Dropbox account that you know the logon details of, then you could try visiting here to claim a special 100Gb annual bonus for DropBox users.
All you need to do is sign in and have the web page be able to save a doc to your DropBox account, and you’ll get another 100Gb free OneDrive for a year. Boom!
What to do with all this massive amount of storage? Well, phone pictures might take up lots of space, but what about storing your music on there so you can access from anywhere? Now, wouldn’t that be cool?