How expensive are color and black ink cartridges?

It depends on what kind of printer you have, and the specific cartridge you are buying. This is a question for Google, not Fluther.

What @jeffgoldblumsprivatefacilities said :)

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Around $0.70/mL, as of 2006, vs. $0.40/mL for blood.

Cheaper if you buy in bulk, although at a higher capital cost.

it does depend as stated my colour and black run about $30 .. but i can get them on sale around 15 at times i have a lexmark
..

They are expensive enough, that if you actually purchase any of them…consider yourself a rape victim.

Really expensive if you buy from the printer’s manufacturer. However, there are 3rd party manufacturers that produce and sell compatible cartridges you can use for a fraction of the price. For example, the cartridges for my printer cost 30 to 40€ a piece. The 3rd party compatible cartridges only cost me 6€ a piece and they have given me no problems at all. If you can find them, go for them.
For example, this noname cartridge for an Epson D68 only costs 2.45€.

Too expensive.

They are pretty expensive but can be refilled for cheap. Although refilling your cartridge may void warantee/affect printer performance/etc

It’s totally dependent on your printer. Some are $250 and some are $1.99. I refill the cartridge for my laser printer for $12 rather than paying $190. The ink jet cartridges for my other printer are $1.99 online.