Bad news: Yearly - some features cease working after a year, more on that below -, no multi-pc license is available.
Good news: The free version cleans just as well as the pro version. The benefits of pro are multiuser cleaning (feature continues to work after a year), browser monitoring (feature continues after year), Automatic updates without going to ccleaner website (supposedly ends after a year, though some have claimed otherwise) and finally priority support direct from the developers as opposed to having to come to this, the user forum (lasts one year).
So for your means at home, the free version would probably be fine, especially if most of your PCs have only one user.