================================== Depending on how you use your computer you might find it easier and cheaper to use a separate trailing lead with individually switched sockets for your peripherals - e.g. :
If you don't like trailing leads consider 'Master plugs' from B&Q which have three individually switched outlets. :
Neither of the above is automatic but if you only use a printer / scanner / speakers intermittently then there is no need to switch on *any* peripherals until actually needed and can be switched on / off completely independently of the computer.
Cic.