Lee,
Have you ever tried refilling your carts at home. I use the JR kit from ASDA and for about £8 get 3 refills for our Lexmark, multifunction machine. Also use the colour ones but these kits can only be used on certain akes and models but its worth checking out.
Also we try to keep any colour to a minimum on leaflets as we have not found it makes any difference to the response. Now we just print black on a bright yellow paper so it stands out.
Try www. vistaprint.co.uk. This is a site Brett introduced me to and they see pretty reasonable but have yet to see the quality.
Good luck,
Sarah