It’s just a bottle of ink that you pour into the tank. You can find generic ones for $7-8.
My wife prints 1-2 boxes of paper per year in color. About 10% of those are photograph quality. A laser printer wouldn’t cut it for the photographs so I got her an ecotank.
The tanks hold 130ml of ink so they last a long time. The largest HP cartridge held like 49ml of ink of I recall correctly. Most of them had under 10ml.
If you print infrequently or an absolute ton (like an office) a laser printer is better. If you print a case or two of paper per year and photographs, the inkjet is better.