Thanks scottiesmom, although that is one of the sites I also use, I posted the wrong site to begin with, the site I meant to mention is "
http://new.ukdvdr.co.uk/search.php?search=CLX-2160&brand= " where I recently purchased the coloured toner cartridges from, (£6.14 each not as originally stated as £5.99)
I can't remember now but I think each cartridge is supposed to print about 1,000 pages.
The printer itself is about 2 to 3 years old and as said earlier it's not too bad but as said in one of the many write-ups it does tend to curl the paper quite a bit, so actually making double sided printing a bit difficult at times, but it did not cost me anything so who am I to complain.
(what I have done on one occasion is to print the one side of each copy then leave it/them under a flat weight for about 30 minutes then print the reverse sides) not the best way of printing but it does work.
But as I also said, the quality of paper makes a big difference and I am only using cheap photocopy paper at the moment.
(Better/thicker paper has produced better results with far less curling of the paper)
Still on the subject of ink, when I originally setup my CISS (Continuous Ink Supply System) I also diverted the waste overflow tube into a clear glass jar which not only is it amazing to see how much ink gets wasted each time the printer is turned on and even more-so when a head clean task is run either automatically or manually, this "WASTE INK" although a mixture of all 6 colours it then gets recycled into the black ink bottle without any noticeable difference, although I do occasionally use a new supply of black ink from time-to-time to stop it from getting to diluted with the other colours.
This is the unit that I first setup and it's still going strong without any problems, although I had a quick look for replacement inks the other day and they seem to be a bit illusive at the moment.
How to: Install a Continuous Ink Supply System (CISS) for the Epson R300 edit:
Link changed.