This is a rhetoric, but nevertheless a totally frustrating, question.

Why are printer cartidges so expensive? I went to my local electronics shop today to get both cartridges, and they had a 'package deal'- buy both for a discounted price.

Whilst I was there I glanced at the printers for sale, and there was one priced at $59.00. My cartridges cost $58.00. There is something drastically wrong here!

Has anyone tried the re-inking kits? Do they work? Are they easy to use, or do you need gloves and protective aprons?

Nothing wrong, the manufacturers make their money from the inks, not from the printer - you buy their reasonably priced printer and you normally have to buy their inks.

Some of the cartridges cannot be refilled, they have sensors for the computer to tell you when the ink is low, if you try refilling them the computer still thinks they are empty.

I buy my inks in multi-packs, all the colours in one package - and it is much cheaper to use printers which have lots of individual cartridges instead of one colour cartridge. If you end up running out of one colour you don't have to throw out unused inks. One local supplier does a three for two offer from time to time, I then stock up.

We regularly buy bulk ink in bottles and refill our ink cartridges ourselves using a syringe. Right now, we have only a black cartridge in our printer, since we use color printing so rarely, so that makes it easier. The only equipment we use besides the ink and the syringe is a napkin or paper towel, just to work on in case of a spill.
What Sue says about the sensors is true. Several years ago, we could refill a cartridge what seemed like indefinitely, but now after about three times they refuse to print after being refilled. Still, it saves us a lot of money.
The establishment I buy my ink at also has a refill service and will refill your cartridges for you if you don't have the courage!