Why not just get a colour laser?
You can pick up a good colour laser for £112.00 (see HP COLOUR LASERJET 1600) with free delivery - quicker, better and cheaper to run? And yes toner is expensive but you will still get more prints out of the "free toner" then you will out of the inkjet.
£70 printer (included "free cartridges") and £40 left for ink cartridges. or £112 for the a laser with more prints and faster?
I hate the idea of throwing away printers when they run out but sadly the companies make it more economical that way.