Thought this may be of interest if you like living on the bleeding edge and would like to use Office for free. The Home Premium version of the new Office Preview allows 5 installs per Windows Live account and gives full preview/beta versions of the new Office Apps.
The Office Customer Preview will expire approximately 60 days after the official release date of Office 2013.
The Office 15 Roadmap says that the product will RTM at the end of 2012 or Q1 2013 meaning that the preview will be good until at least March 2013.
This definitely won’t be for everyone but is an interesting way to get Office for free for the next 7 months or so!
Lots of information available: