Why is printer ink (cartridge form) so expensive?

The companies that make the printers also make the ink.
Since they do not make a lot of money from the printers themselves (they would not even if they were more expensive), they get most of their revenues from selling you the ink, the stuff that you need to replenish constantly to use the printer. The ink itself is relatively cheap to make, given the fact that you can buy 3rd party manufactured ink cartridges for as little as 1/10 the price of an original cartridge.
tl;dr Ink cartridges are intentionally overpriced for maximum profit.

My mom has a HP printer/scanner that refuses to scan if the printer is out of ink. Think about that.

Same reason razors are cheap and cartridges are expensive: first they entice you, then they take you to the cleaners.

If I am typical, HP has not made much of a profit. I am still using my original printer, from 1998. It works just fine.

@johnpowell The fambly computer has a Lexmark that won’t print anything unless both black and color cartridges are fairly full.

I think @ragingloli hit it on the head and it annoys me greatly! And mine won’t print at all if any color is out. That is maddening, sometimes I just want a copy of something and I don’t care if it is the proper color or not!

I take the empty cartridges to a place called Cartridge World where they are refilled. Saves money and keeps the old cartridge out of the landfill.

Lexmark tried to use the DMCA to make third party ink illegal. Luckily they failed.

Because, obviously, printer ink is made from unicorn blood.

Because the cost of actually making a gallon of said ink is roughly $2,700

We had a printer that cost £30. The new cartidge cost £35 meaning it was cheaper to buy a new printer. What kind of a crazy world is that?

I have had some sucess with injecting ink into inkjet cartridges. You buy a special kit, it’s fairly cheap

@Stinley – I have ink stains on my walls, clothing and fingers from those damned kits. They are definitely less expensive and hopefully some might think the blotches on my face look sort of attractive???

@rooeytoo We’ll just call you Rorschach.

Doesn’t Staples or Office Max or someone refill ink cartridges for you?

@Nullo – I was going to call myself that, but I couldn’t remember how to spell it and I was too lazy to google, heheheh, thank you for the spelling lesson! (It still doesn’t look right though, are you sure that is the correct spelling?!)

(It is.)