He could have chosen the old way and buying the cartridges himself on a regular basis, but he chose the subscription model and now he wines about it.
What you need to understand about the subscription model is that you DON'T own the cartridge and you DON'T pay for the cartridge. You pay for printed pages. If the ink runs out, the printer automatically orders a set of new ones, for no additional cost. You receive a package to your preferred postal address, that contains the new ink and a sealable, labeled, post-stamped bag in which you will put the old ones and send it back to HP.
I absolutely love this model. I pay the minimal 2USD for it (if I exceed the monthly printable 50 pages, I get another 10p/$1, or upgrade my subscription. Unused quota accumulates up to 100p), and I get a monthly email about the detailed pricing.
Also, this way the used cartridges (dangerous waste) are handled properly and an environmentally friendly way.