$0.07 / GB was calculated from costs and covers all expenses for an offsite backup service like this. I'm an open book and the project is open-source, so if you have any questions, feel free to ask. :)
Here's a pic: http://www.piqd.com/tarbackup_server.png
You can check out more info and see other pics of the hardware here:
http://www.reddit.com/r/linux/comments/zt1md/hey_linux_im_ma...