AirPrint software

You could purchase an Airport Express and plug a USB printer into it and be able to print wirelessly to it from MAC/PC and IOS devices.  Yet you can buy a Wireless AirPrint capable inkjet for around the same price.

You could also use your existing Mac as a print server but as mentioned you would need to leave it powered on.  Fortunately when in sleep mode the Mac only draws a watt or two so there is not big cost to leaving it powered on.  handyPrint or Printopia will enable printing from your IOS devices.

--
Jim
'There are no rules for good photographs, there are only good photographs.'
-- Ansel Adams