Have you yet tried HP Instant Ink service? I've been using it for few months and now amazed by it. It helped me to save so much on inks.
It offers amazing deals which could save you fortunes overtime. Deals such as 50 colour pages PCM start for as low as £1.99PCM. No contract, cancel anytime! If you chose to stay on pay-as-you-go, a lifetime 15 FREE colour pages every month! Cool, huh?
HP Printers communicate with HP servers directly and inks get delivered to your door for FREE when they are about to run-out. Never need to worry about running out of ink. There is no catch, I've used it. I wouldn't be recommending otherwise.
They have an incentive system which gives you a 4-month of free printing at the beginning. Sign up for the first 4 months and just cancel after that if you aren't happy, as simple as that.
Follow the link below to sign up and you get 4 free months of printing (3 month from the company + 1 month from my referral).
http://try.hpinstantink.com/lpnBC
Remember, if you do not go through the link above, you will not get extra free month.
Good Luck and Happy Saving!! ;)