I've just rolled over and gone with HP's Instant Ink
£1.99 a month for 50 pages (and I think you can roll 100 over between months) - and easily covers my occasional printing needs.
I know I could print pages cheaper using 3rd-party carts and a less draconian manufacturer - but it nicely shifts annoyances with one colour running out before the others, blocked nozzles etc onto HP.
I pay £24 a year - and I have one less thing to worry about.