Estimate total printer ownership cost over a year.
Printer ownership costs three things: the hardware spread over its life, the ink, and the paper. Ink usually dominates, which is why the business model puts cheap printers in homes and recovers the money on cartridges — the ink-share figure makes that visible. Dividing the whole annual cost by the pages actually printed gives the true cost per page, and it is brutal at low volumes: printing 30 pages a month can cost over 40 cents a page once the printer itself is counted.
Consumables
Ink per page = cartridge set price / pages per set; consumables = (ink per page + paper) x annual pages
True cost per page
Cost per page = (consumables + printer price / expected life) / annual pages
Usually on cost, often at some risk to print quality and warranty. Enter the cheaper price to see the effect — halving cartridge cost typically cuts the total cost per page by a third or more.
Above roughly 100 pages a month, generally yes. Toner costs more per cartridge but far less per page, and it does not dry out — which is the hidden cost of a lightly used inkjet.
Because at low volumes it is a large share of the total. A 180 printer over four years is 45 a year, which at 30 pages a month is more than the ink.