Microsoft has tweaked Office for iPad, adding the ability to sign up for a month-by-month subscription from within the app.
While Office for iPad has been free since its launch back in March, the free version only offered document viewing, not editing. If you wanted to make changes, you needed to have an existing Office 365 subscription.
You now have the option of signing up for a month-by-month subscription direct from within the app. That costs $12 a month for Office 365 Home or $9 a month for the more restricted Office 365 Personal. That's a more expensive choice than the annual subscription ($119 for Home, $89 for Personal), but some people prefer not being tied to a contract. Note that if you already had a month-by-month package, Office for iPad was always usable — this is just another way of buying a new subscription.
Office for iPad now supports monthly subscriptions [Office Blogs]