This doesn't actually work most of the time.
When you buy a new printer, the toner cartridges (or the ink cartridges) are not anywhere near the 80% that you're quoting - not that I'm disputing what you say, but for most other makes/models it's about 25%.

Using the same calc, it'd be maybe 37.94/400, nearer 10 cents per copy.

These guys aren't *that* dumb, although their habit of putting killer chips on otherwise re-usable toner cartridges to force you to replace them every time does make me want to spit.
(username failed moderation, Thu 1 Mar 2012, 8:23, 2 replies)

Not HP, I think
I've had a couple of HP inkjet printers recently, and both came with standard (ie full) colour and black cartridges. In both cases the printers cost less than even Tesco cartridges. Two different models, by the way.
(ubergeekian, Thu 1 Mar 2012, 9:36, closed)

Must have changed then
because HP were, to my knowledge, the inventors of the practice.

If it's cheaper to buy a new printer than it is to buy new toner cartridge, the whole cost of manufacturing printers is a loss for the company making them. Makes no sense at all.

It's actually a really good troll. Post this on a lot of forums, and assuming they haven't seen it before you will create a shit storm of nerdery.
(username failed moderation, Thu 1 Mar 2012, 9:56, closed)

He's Right, I'm Wrong

Just checked the box sitting on my desk. The toner the printer ships with is only 700 pages not 1200.
( Legless Mister Stabby - shanks for the memory, Thu 1 Mar 2012, 10:07, closed)