Google Drive is asking $2.50 a month for 25 gigabytes, $5.00 a month for 100 gigabytes, and $50 a month for 1 terabyte. Ubuntu One works a little differently if you buy 1 song from the music store they give you 20 gigabytes for free for 6 months then charge you $4.00 a month. Apple's iCloud is charging $3.25 for 10 gigabytes of storage.
On top of the 3 services offered above there is another cloud service that is offering 50 gigabytes of cloud storage for free. Check out Gizmodo's article "Hands On With Kim Dotcom’s New Mega: This Service Could Dismantle Copyright Forever" In short when you use the mega service the file is encrypted from a key on the local machine before it goes to mega, which they think will keep them out of trouble by not knowing what the users upload. The service might be reachable at http://kim.com/mega but what this article is about is running your own cloud service, with your own machine or server.
While running your own cloud might not be as reliable as using one of the services mentioned above it definitely does have it's benefits. One of those benefits would be the space available to store stuff, but one of the downfalls could be a hard drive crash, especially if there isn't a RAID array in place. ownCloud has a ton of great features such as the built in support to display documents such as word or excel. Check out the full list of features at http://owncloud.org/features/.
Getting started with your own cloud can be really simple. The easiest way to get going with ownCloud is the VM image as well pre-configured USB images and Amazon EC2 images which can be downloaded at http://susestudio.com/a/TadMax/owncloud-in-a-box. For the more adventurous check out the installation page, which covers just about every major Linux distro as well as Windows and Mac.
- Download: http://owncloud.org/support/install/
- Installation Manual: http://doc.owncloud.org/server/4.5/admin_manual/installation.html
- Download the Desktop Client: https://owncloud.com/overview/desktop-clients
- Android App: https://play.google.com/store/apps/details?id=com.owncloud.android
- iOS App: http://itunes.apple.com/us/app/owncloud/id543672169?ls=1&mt=8