Hopefully this will be helpful to all those who've been taking advantage of the cheap Photosmart Printers recently.
I bought a pack of these the other day after scouting about for ages and seeing these at £11 per cartridge everywhere. These work out at £6.79 each.
If you just want the black cartridge you can buy it on its own for £7.99.
You also get more ink with these cartridges than the originals. On the website it states 18ml of ink but the black cartridge I received has 20ml! :)
Next cheapest I can find is £10.69 each delivered on Amazon, so this offer would save you £19.50 and you get more ink :)