We just buy a new printer whenever the old one runs dry.
If you ask one of the printer manufacturers why its ink costs more than fine wine, they'll tell you it's because a lot goes into those cartridges other than ink (though that doesn't answer why it can afford to include a cartridge with the printer, but not a USB cable). And the manufacturers are right -- a lot of the printing mechanism is right there in the cartridge.
Not to mention the kill switches they have to put into them to force you to throw them away before they're actually empty.
Let's hope this technique doesn't spread to the automotive industry.
Yes, it turns out that many of the ink cartridges made by HP and Lexmark have switches in them that make the cartridges fail after a certain period of time, whether they're empty or not. This isn't just some crazy conspiracy theory, either. HP's senior "ink scientist" (yes, that's actually his real title), Nils Miller, admitted to this during an interview.