This backup service is based on GB not on the number of devices you use and says you can have an unlimited number of PC's, Macs, Iphones, ipasd, and android devices. 5GB is free. 150GB ($4.95 a month) and 500GB is $14.95 a month.)
This incredible utility for Windows is something I run every few months. My tech guru go-to guy, Luke Allen, put me onto it. This free program will go through and clean up things that are unneeded and help speed up your computer (as much as possible with your configuration) - there are also some privacy features in it as well. I highly recommend it.