Medium sized grey 'O'Neill' Backpack with 3 separate zip close compartments. This Bag also has a pocket for a mobile phone, a clip for your keys and an inside pocket for money. As well as a name tag so you never get it confused with anyone else.
Only downside on this bargain is Availability: 4 or more weeks, but if you order now there's a good chance it will arrive in time for the new school term (if this is what you wanted to buy it for)
I've ordered stuff from WH Smith with "Availability: 4 or more weeks" in the past and have actually picked it up within the week